The Mizar article:

Meet Continuous Lattices Revisited

by
Artur Kornilowicz

Received January 6, 2000

Copyright (c) 2000 Association of Mizar Users

MML identifier: WAYBEL30
[ MML identifier index ]


environ

 vocabulary BOOLE, TARSKI, RELAT_2, ORDERS_1, QUANTAL1, YELLOW_1, WAYBEL_0,
      FILTER_2, LATTICE3, ORDINAL2, YELLOW_0, LATTICES, WAYBEL_2, REALSET1,
      YELLOW_9, WAYBEL11, BHSP_3, WAYBEL_9, PRE_TOPC, PROB_1, WAYBEL19,
      PRELAMB, CANTOR_1, SETFAM_1, DIRAF, SUBSET_1, FINSET_1, COMPTS_1,
      YELLOW_6, TOPS_1, WAYBEL29, YELLOW13, WAYBEL21, RELAT_1, PARTFUN1,
      FUNCT_3, FUNCT_1, TOPS_2, WAYBEL_3, RLVECT_3, TDLAT_3, CONNSP_2,
      FILTER_0, WAYBEL_8, WAYBEL_6, WAYBEL30;
 notation TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, RELAT_1, RELSET_1, FUNCT_1,
      FUNCT_2, FUNCT_3, STRUCT_0, FINSET_1, REALSET1, ORDERS_1, PRE_TOPC,
      TOPS_1, TOPS_2, COMPTS_1, CONNSP_2, TDLAT_3, LATTICE3, BORSUK_1,
      CANTOR_1, YELLOW_0, WAYBEL_0, YELLOW_1, WAYBEL_1, YELLOW_3, YELLOW_4,
      WAYBEL_2, WAYBEL_3, YELLOW_6, YELLOW_8, WAYBEL_6, WAYBEL_8, WAYBEL_9,
      WAYBEL11, YELLOW_9, WAYBEL19, WAYBEL21, YELLOW13, WAYBEL29;
 constructors CANTOR_1, GROUP_1, TOPS_1, TOPS_2, TDLAT_3, YELLOW_4, YELLOW_8,
      WAYBEL_1, WAYBEL_6, WAYBEL_8, WAYBEL19, ORDERS_3, URYSOHN1, WAYBEL21,
      YELLOW13, WAYBEL29, MEMBERED;
 clusters STRUCT_0, FINSET_1, BORSUK_1, SUBSET_1, TEX_1, TOPS_1, CANTOR_1,
      LATTICE3, YELLOW_0, YELLOW_1, YELLOW_2, YELLOW_3, YELLOW_4, YELLOW_6,
      WAYBEL_0, WAYBEL_2, WAYBEL_3, WAYBEL_8, WAYBEL10, WAYBEL11, WAYBEL14,
      YELLOW_9, WAYBEL19, YELLOW12, WAYBEL_4, RELSET_1, YELLOW13, MEMBERED,
      ZFMISC_1;
 requirements BOOLE, SUBSET;
 definitions TARSKI, PRE_TOPC, LATTICE3, YELLOW_0, WAYBEL_0, WAYBEL_2,
      WAYBEL_3, YELLOW_8, YELLOW_9, WAYBEL19, WAYBEL11, YELLOW13, XBOOLE_0;
 theorems TARSKI, PRE_TOPC, ORDERS_1, TOPS_1, TOPS_2, BORSUK_1, CONNSP_2,
      TEX_2, TDLAT_3, COMPTS_1, CANTOR_1, LATTICE3, RELAT_1, ZFMISC_1, FUNCT_1,
      FUNCT_2, FUNCT_3, RELSET_1, YELLOW_0, YELLOW_1, YELLOW_2, YELLOW_3,
      YELLOW_4, YELLOW_6, YELLOW_8, WAYBEL_0, WAYBEL_2, WAYBEL_3, WAYBEL_8,
      YELLOW13, WAYBEL11, WAYBEL12, WAYBEL14, YELLOW_9, WAYBEL19, YELLOW12,
      WAYBEL21, WAYBEL29, SETFAM_1, XBOOLE_0, XBOOLE_1;
 schemes SETFAM_1, FINSET_1, YELLOW_2;

begin

theorem Th1:
 for x being set, D being non empty set holds
  x /\ union D = union {x /\ d where d is Element of D: not contradiction}
  proof
    let x be set,
        D be non empty set;
    hereby
      let a be set;
      assume a in x /\ union D;
then A1:   a in x & a in union D by XBOOLE_0:def 3;
      then consider Z being set such that
A2:     a in Z & Z in D by TARSKI:def 4;
A3:   a in x /\ Z by A1,A2,XBOOLE_0:def 3;
        x /\ Z in {x /\ d where d is Element of D: not contradiction} by A2;
      hence a in union {x /\ d where d is Element of D: not contradiction}
        by A3,TARSKI:def 4;
    end;
    let a be set;
    assume a in union {x /\ d where d is Element of D: not contradiction};
    then consider Z being set such that
A4:   a in Z & Z in {x /\ d where d is Element of D: not contradiction}
        by TARSKI:def 4;
    consider d being Element of D such that
A5:   Z = x /\ d and not contradiction by A4;
A6: a in x & a in d by A4,A5,XBOOLE_0:def 3;
    then a in union D by TARSKI:def 4;
    hence a in x /\ union D by A6,XBOOLE_0:def 3;
  end;

theorem Th2:
 for R being non empty reflexive transitive RelStr,
     D being non empty directed Subset of InclPoset Ids R holds
   union D is Ideal of R
  proof
    let R be non empty reflexive transitive RelStr,
        D be non empty directed Subset of InclPoset Ids R;
A1: Ids R = {X where X is Ideal of R: not contradiction} by WAYBEL_0:def 23;
      D c= the carrier of InclPoset Ids R;
then A2: D c= Ids R by YELLOW_1:1;
A3: D c= bool the carrier of R
    proof
      let d be set;
      assume d in D;
      then d in Ids R by A2;
      then ex I being Ideal of R st d = I & not contradiction by A1;
      hence thesis;
    end;
    consider d being Element of D;
      d in D;
    then d in Ids R by A2;
    then consider I being Ideal of R such that
A4:   d = I and not contradiction by A1;
    consider i being Element of I;
A5: i in d by A4;
A6: for X being Subset of R st X in D holds X is directed
    proof
      let X be Subset of R;
      assume X in D;
      then X in Ids R by A2;
      then ex I being Ideal of R st X = I & not contradiction by A1;
      hence thesis;
    end;
A7: for X, Y being Subset of R st X in D & Y in D
     ex Z being Subset of R st Z in D & X \/ Y c= Z
    proof
      let X, Y be Subset of R;
      assume
A8:     X in D & Y in D;
      then reconsider X1 = X, Y1 = Y as Element of InclPoset Ids R
       ;
      consider Z1 being Element of InclPoset Ids R such that
A9:     Z1 in D & X1 <= Z1 & Y1 <= Z1 by A8,WAYBEL_0:def 1;
        Z1 in Ids R by A2,A9;
      then ex I being Ideal of R st Z1 = I & not contradiction by A1;
      then reconsider Z = Z1 as Subset of R;
      take Z;
      thus Z in D by A9;
        X1 c= Z1 & Y1 c= Z1 by A9,YELLOW_1:3;
      hence X \/ Y c= Z by XBOOLE_1:8;
    end;
      for X being Subset of R st X in D holds X is lower
    proof
      let X be Subset of R;
      assume X in D;
      then X in Ids R by A2;
      then ex I being Ideal of R st X = I & not contradiction by A1;
      hence thesis;
    end;
    hence thesis by A3,A5,A6,A7,TARSKI:def 4,WAYBEL_0:26,46;
  end;

Lm1:
  now
    let R be non empty reflexive transitive RelStr,
        D be non empty directed Subset of InclPoset Ids R,
        UD be Element of InclPoset Ids R such that
A1:   UD = union D;
    thus D is_<=_than UD
    proof
      let d be Element of InclPoset Ids R;
      assume
A2:     d in D;
        d c= UD
      proof
        let a be set;
        assume a in d;
        hence a in UD by A1,A2,TARSKI:def 4;
      end;
      hence d <= UD by YELLOW_1:3;
    end;
  end;

Lm2:
  now
    let R be non empty reflexive transitive RelStr,
        D be non empty directed Subset of InclPoset Ids R,
        UD be Element of InclPoset Ids R such that
A1:   UD = union D;
    thus for b being Element of InclPoset Ids R st b is_>=_than D holds UD <=
b
    proof
      let b be Element of InclPoset Ids R such that
A2:     for a being Element of InclPoset Ids R st a in D holds b >= a;
        UD c= b
      proof
        let x be set;
        assume x in UD;
        then consider Z being set such that
A3:       x in Z & Z in D by A1,TARSKI:def 4;
        reconsider Z as Element of InclPoset Ids R by A3;
          b >= Z by A2,A3;
        then Z c= b by YELLOW_1:3;
        hence x in b by A3;
      end;
      hence UD <= b by YELLOW_1:3;
    end;
  end;

:: Exercise 2.16 (i), p. 16
definition let R be non empty reflexive transitive RelStr;
 cluster InclPoset Ids R -> up-complete;
coherence
  proof
    set I = InclPoset Ids R;
    let D be non empty directed Subset of I;
    reconsider UD = union D as Ideal of R by Th2;
      Ids R = {X where X is Ideal of R: not contradiction} by WAYBEL_0:def 23;
    then UD in Ids R;
    then UD in the carrier of InclPoset Ids R by YELLOW_1:1;
    then reconsider UD as Element of I;
    take UD;
    thus thesis by Lm1,Lm2;
  end;
end;

theorem Th3:
 for R being non empty reflexive transitive RelStr,
     D being non empty directed Subset of InclPoset Ids R holds
  sup D = union D
  proof
    let R be non empty reflexive transitive RelStr,
        D be non empty directed Subset of InclPoset Ids R;
A1: ex_sup_of D,InclPoset Ids R by WAYBEL_0:75;
A2: Ids R = {X where X is Ideal of R: not contradiction} by WAYBEL_0:def 23;
    reconsider UD = union D as Ideal of R by Th2;
      UD in Ids R by A2;
    then UD in the carrier of InclPoset Ids R by YELLOW_1:1;
    then reconsider UD as Element of InclPoset Ids R;
      D is_<=_than UD &
    for b being Element of InclPoset Ids R st b is_>=_than D holds UD <= b
      by Lm1,Lm2;
    hence sup D = union D by A1,YELLOW_0:def 9;
  end;

theorem Th4:
 for R being Semilattice,
     D being non empty directed Subset of InclPoset Ids R,
     x being Element of InclPoset Ids R holds
   sup ({x} "/\" D) = union {x /\ d where d is Element of D: not contradiction}
  proof
    let R be Semilattice,
        D be non empty directed Subset of InclPoset Ids R,
        x be Element of InclPoset Ids R;
    set I = InclPoset Ids R,
        A = {x /\ d where d is Element of D: not contradiction},
        xD = {x "/\" d where d is Element of I: d in D};
      xD c= the carrier of I
    proof
      let a be set;
      assume a in xD;
      then ex d being Element of I st a = x "/\" d & d in D;
      hence thesis;
    end;
    then reconsider xD as Subset of I;
A1: ex_sup_of {x} "/\" D,I by WAYBEL_2:1;
    then ex_sup_of xD,I by YELLOW_4:42;
then A2: sup xD is_>=_than xD by YELLOW_0:def 9;
    hereby
      let a be set;
      assume
A3:     a in sup ({x} "/\" D);
        ex_sup_of D,I by WAYBEL_0:75;
      then sup ({x} "/\" D) <= x "/\" sup D by A1,YELLOW_4:53;
      then sup ({x} "/\" D) c= x "/\" sup D by YELLOW_1:3;
      then a in x "/\" sup D by A3;
      then a in x /\ sup D by YELLOW_2:45;
then A4:   a in x & a in sup D by XBOOLE_0:def 3;
      then a in union D by Th3;
      then consider d being set such that
A5:     a in d and
A6:     d in D by TARSKI:def 4;
      reconsider d as Element of I by A6;
      set A = {x /\ w where w is Element of D: not contradiction};
A7:   x /\ d in A by A6;
        a in x /\ d by A4,A5,XBOOLE_0:def 3;
      hence a in union A by A7,TARSKI:def 4;
    end;
    let a be set;
    assume a in union A;
    then consider Z being set such that
A8:   a in Z and
A9:   Z in A by TARSKI:def 4;
    consider d being Element of D such that
A10:   Z = x /\ d and not contradiction by A9;
    reconsider d as Element of I;
A11: x /\ d = x "/\" d by YELLOW_2:45;
A12: xD = {x} "/\" D by YELLOW_4:42;
    then x "/\" d in {x} "/\" D;
    then sup xD >= x "/\" d by A2,A12,LATTICE3:def 9;
    then x "/\" d c= sup xD by YELLOW_1:3;
    then a in sup xD by A8,A10,A11;
    hence a in sup ({x} "/\" D) by YELLOW_4:42;
  end;

:: Exercise 4.8 (i), p. 33
definition let R be Semilattice;
 cluster InclPoset Ids R -> satisfying_MC;
coherence
  proof
    set I = InclPoset Ids R;
    let x be Element of I,
        D be non empty directed Subset of I;
    thus x "/\" sup D = x /\ sup D by YELLOW_2:45
        .= x /\ union D by Th3
        .= union {x /\ d where d is Element of D: not contradiction} by Th1
        .= sup ({x} "/\" D) by Th4;
  end;
end;

definition let R be non empty trivial RelStr;
 cluster -> trivial TopAugmentation of R;
coherence
  proof
    let T be TopAugmentation of R;
      the RelStr of T = the RelStr of R by YELLOW_9:def 4;
    hence thesis by TEX_2:4;
  end;
end;

theorem
   for S being Scott complete TopLattice, T being complete LATTICE,
     A being Scott TopAugmentation of T
   st the RelStr of S = the RelStr of T holds
  the TopRelStr of A = the TopRelStr of S
  proof
    let S be Scott complete TopLattice,
        T be complete LATTICE,
        A be Scott TopAugmentation of T such that
A1:   the RelStr of S = the RelStr of T;
A2: the RelStr of A = the RelStr of S by A1,YELLOW_9:def 4;
      the topology of S = sigma S by WAYBEL14:23
                     .= sigma T by A1,YELLOW_9:52
                     .= the topology of A by YELLOW_9:51;
    hence the TopRelStr of A = the TopRelStr of S by A2;
  end;

theorem
   for N being Lawson complete TopLattice, T being complete LATTICE,
     A being Lawson correct TopAugmentation of T
   st the RelStr of N = the RelStr of T holds
  the TopRelStr of A = the TopRelStr of N
  proof
    let N be Lawson complete TopLattice,
        T be complete LATTICE,
        A be Lawson correct TopAugmentation of T such that
A1:   the RelStr of N = the RelStr of T;
A2: the RelStr of A = the RelStr of N by A1,YELLOW_9:def 4;
    consider l being lower correct TopAugmentation of T;
    consider S being Scott correct TopAugmentation of T;
A3: the topology of l = omega T & the topology of S = sigma T
      by WAYBEL19:def 2,YELLOW_9:51;
A4: the RelStr of S = the RelStr of T & the RelStr of l = the RelStr of T
      by YELLOW_9:def 4;
A5: N is Refinement of S, l
    proof
      thus the carrier of N = (the carrier of S) \/ (the carrier of l)
        by A1,A4;
        (sigma N) \/ (omega N) is prebasis of N by WAYBEL19:def 3;
      then (sigma T) \/ (omega N) is prebasis of N by A1,YELLOW_9:52;
      hence (the topology of S) \/ (the topology of l) is prebasis of N
       by A1,A3,WAYBEL19:3;
    end;
      (the topology of S) \/ (the topology of l) c= bool the carrier of N
    proof
      let a be set;
      assume a in (the topology of S) \/ (the topology of l);
      then a in the topology of S or a in the topology of l by XBOOLE_0:def 2;
      hence a in bool the carrier of N by A1,A4;
    end;
    then reconsider X = (the topology of S) \/ (the topology of l)
      as Subset-Family of N by SETFAM_1:def 7;
    reconsider X as Subset-Family of N;
      the topology of N = UniCl FinMeetCl X by A5,YELLOW_9:56
                     .= lambda T by A1,A3,WAYBEL19:33
                     .= the topology of A by WAYBEL19:def 4;
    hence the TopRelStr of A = the TopRelStr of N by A2;
  end;

theorem
   for N being Lawson complete TopLattice
  for S being Scott TopAugmentation of N
   for A being Subset of N, J being Subset of S st A = J & J is closed holds
  A is closed
  proof
    let N be Lawson complete TopLattice,
        S be Scott TopAugmentation of N,
        A be Subset of N,
        J be Subset of S such that
A1:   A = J;
A2: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    assume J is closed;
then A3: [#]S \ J is open by PRE_TOPC:def 6;
A4: N is Lawson correct TopAugmentation of S by A2,YELLOW_9:def 4;
      [#]S = the carrier of S by PRE_TOPC:12
      .= [#]N by A2,PRE_TOPC:12;
    hence [#]N \ A is open by A1,A3,A4,WAYBEL19:37;
  end;

definition let A be complete LATTICE;
 cluster lambda A -> non empty;
coherence
  proof
    consider S being Lawson correct TopAugmentation of A;
      InclPoset the topology of S is non trivial;
    hence thesis by WAYBEL19:def 4;
  end;
end;

definition let S be Scott complete TopLattice;
 cluster InclPoset sigma S -> complete non trivial;
coherence
  proof
      InclPoset the topology of S is complete non trivial;
    hence thesis by WAYBEL14:23;
  end;
end;

definition let N be Lawson complete TopLattice;
 cluster InclPoset sigma N -> complete non trivial;
coherence
  proof
    consider S being Scott TopAugmentation of N;
A1: the RelStr of S = the RelStr of N by YELLOW_9:def 4;
      InclPoset sigma S is complete non trivial;
    hence thesis by A1,YELLOW_9:52;
  end;
 cluster InclPoset lambda N -> complete non trivial;
coherence
  proof
    consider S being Lawson correct TopAugmentation of N;
      InclPoset the topology of S is complete non trivial;
    hence thesis by WAYBEL19:def 4;
  end;
end;

theorem Th8:
 for T being non empty reflexive RelStr holds
 sigma T c= {W\uparrow F where W, F is Subset of T: W in sigma T & F is finite}
  proof
    let T be non empty reflexive RelStr;
    let s be set; assume
A1:   s in sigma T;
      s\uparrow {}T = s;
    hence thesis by A1;
  end;

theorem Th9:
 for N being Lawson complete TopLattice holds lambda N = the topology of N
  proof
    let N be Lawson complete TopLattice;
      N is Lawson correct TopAugmentation of N by YELLOW_9:44;
    hence thesis by WAYBEL19:def 4;
  end;

theorem Th10:
 for N being Lawson complete TopLattice holds sigma N c= lambda N
  proof
    let N be Lawson complete TopLattice;
    set Z = {W\uparrow F where W, F is Subset of N: W in
 sigma N & F is finite};
      Z is Basis of N by WAYBEL19:32;
    then Z c= the topology of N by CANTOR_1:def 2;
then A1: Z c= lambda N by Th9;
      sigma N c= Z by Th8;
    hence sigma N c= lambda N by A1,XBOOLE_1:1;
  end;

theorem
   for M, N being complete LATTICE st the RelStr of M = the RelStr of N holds
  lambda M = lambda N
  proof
    let M, N be complete LATTICE such that
A1:   the RelStr of M = the RelStr of N;
A2: lambda M = UniCl FinMeetCl ((sigma M) \/ (omega M)) &
     lambda N = UniCl FinMeetCl ((sigma N) \/ (omega N)) by WAYBEL19:33;
      sigma M = sigma N & omega M = omega N by A1,WAYBEL19:3,YELLOW_9:52;
    hence lambda M = lambda N by A1,A2;
  end;

theorem Th12:
 for N being Lawson complete TopLattice, X being Subset of N holds
  X in lambda N iff X is open
  proof
    let N be Lawson complete TopLattice,
        X be Subset of N;
      lambda N = the topology of N by Th9;
    hence X in lambda N iff X is open by PRE_TOPC:def 5;
  end;

definition
 cluster trivial TopSpace-like -> Scott (reflexive non empty TopRelStr);
coherence
  proof
    let T be reflexive non empty TopRelStr;
    assume T is trivial TopSpace-like;
    then reconsider W = T as trivial reflexive non empty TopSpace-like
TopRelStr;
      W is Scott
    proof
      let S be Subset of W;
      thus S is open implies S is upper;
      thus thesis by TDLAT_3:17;
    end;
    hence thesis;
  end;
end;

definition
 cluster trivial -> Lawson (complete TopLattice);
coherence
  proof
    let T be complete TopLattice;
    assume T is trivial;
    then reconsider W = T as trivial complete TopLattice;
A1: the topology of W = {{}, the carrier of W} by TDLAT_3:def 2;
    consider N being Lawson correct TopAugmentation of W;
      the RelStr of T = the RelStr of N by YELLOW_9:def 4;
    then the topology of T = the topology of N by A1,TDLAT_3:def 2
     .= lambda T by WAYBEL19:def 4
     .= UniCl FinMeetCl ((sigma T) \/ (omega T)) by WAYBEL19:33;
    then FinMeetCl ((omega T) \/ (sigma T)) is Basis of T by YELLOW_9:22;
    hence (omega T) \/ (sigma T) is prebasis of T by YELLOW_9:23;
  end;
end;

definition
 cluster strict continuous lower-bounded meet-continuous Scott
  (complete TopLattice);
existence
  proof
    consider A being strict trivial TopLattice;
    take A;
    thus thesis;
  end;
end;

definition
 cluster strict continuous compact Hausdorff Lawson (complete TopLattice);
existence
  proof
    consider R being strict trivial complete TopLattice;
    take R;
    thus thesis;
  end;
end;

EmptySch { A() -> Scott TopLattice, X() -> set, F(set) -> set }:
 { F(w) where w is Element of A(): w in {} } = {}
  proof
   thus { F(w) where w is Element of A(): w in {} } c= {}
   proof
     let a be set such that
A1:    a in { F(w) where w is Element of A(): w in {} };
     assume not a in {};
     consider w being Element of A() such that
A2:    a = F(w) & w in {} by A1;
     thus thesis by A2;
   end;
   thus thesis by XBOOLE_1:2;
  end;

theorem Th13:
 for N being meet-continuous LATTICE, A being Subset of N st
  A has_the_property_(S) holds uparrow A has_the_property_(S)
  proof
    let N be meet-continuous LATTICE,
        A be Subset of N such that
A1:  for D being non empty directed Subset of N st sup D in A
      ex y being Element of N st y in D &
       for x being Element of N st x in D & x >= y holds x in A;
    let D be non empty directed Subset of N; assume
     sup D in uparrow A;
    then consider a being Element of N such that
A2:   a <= sup D & a in A by WAYBEL_0:def 16;
    reconsider aa = {a} as non empty directed Subset of N by WAYBEL_0:5;
      a = sup ({a} "/\" D) by A2,WAYBEL_2:52;
    then consider y being Element of N such that
A3:   y in aa "/\" D &
      for x being Element of N st x in aa "/\"
 D & x >= y holds x in A by A1,A2;
      aa "/\" D = {a "/\" d where d is Element of N: d in D} by YELLOW_4:42;
    then consider d being Element of N such that
A4:   y = a "/\" d & d in D by A3;
    take d;
    thus d in D by A4;
    let x be Element of N such that
A5:   x in D & x >= d;
      y >= y by ORDERS_1:24;
then A6: y in A by A3;
      d >= y by A4,YELLOW_0:23;
    then x >= y by A5,ORDERS_1:26;
    hence x in uparrow A by A6,WAYBEL_0:def 16;
  end;

definition let N be meet-continuous LATTICE,
               A be property(S) Subset of N;
 cluster uparrow A -> property(S);
coherence by Th13;
end;

:: Proposition 2.1 (i), p. 153
theorem Th14:
 for N being meet-continuous Lawson (complete TopLattice),
     S being Scott TopAugmentation of N,
     A being Subset of N st A in lambda N holds
  uparrow A in sigma S
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        A be Subset of N such that
A1:   A in lambda N;
A2: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    then reconsider Y = A as Subset of S;
    reconsider UA = uparrow A as Subset of S by A2;
A3: uparrow A = uparrow Y by A2,WAYBEL_0:13;
A4: S is meet-continuous by A2,YELLOW12:14;
      A is open by A1,Th12;
    then A is property(S) by WAYBEL19:36;
    then Y is property(S) by A2,YELLOW12:19;
    then uparrow Y is property(S) by A4,Th13;
    then UA is open by A3,WAYBEL11:15;
    then uparrow A in the topology of S by PRE_TOPC:def 5;
    hence uparrow A in sigma S by WAYBEL14:23;
  end;

theorem Th15:
 for N being meet-continuous Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N
   for A being Subset of N, J being Subset of S st A = J holds
  A is open implies uparrow J is open
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        A be Subset of N,
        J be Subset of S such that
A1:   A = J;
A2: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    assume A is open;
    then A in lambda N by Th12;
    then uparrow A in sigma S by Th14;
    then uparrow J in sigma S by A1,A2,WAYBEL_0:13;
    hence uparrow J is open by WAYBEL14:24;
  end;

theorem Th16:
 for N being meet-continuous Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N
   for x being Point of S, y being Point of N
    for J being Basis of y st x = y holds
  {uparrow A where A is Subset of N: A in J} is Basis of x
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        x be Point of S,
        y be Point of N,
        J be Basis of y such that
A1:   x = y;
A2: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    set Z = {uparrow A where A is Subset of N: A in J};
    set K = Z;
      K is Subset-Family of S
    proof
        K c= bool the carrier of S
      proof
        let k be set;
        assume k in K;
        then consider A being Subset of N such that
A3:       k = uparrow A and A in J;
        thus k in bool the carrier of S by A2,A3;
      end;
      hence thesis by SETFAM_1:def 7;
    end;
    then reconsider K as Subset-Family of S;
      K is Basis of x
    proof
      thus K c= the topology of S
      proof
        let k be set;
        assume k in K;
        then consider A being Subset of N such that
A4:       k = uparrow A and
A5:       A in J;
        reconsider A' = A as Subset of S by A2;
          A is open by A5,YELLOW_8:21;
        then uparrow A' is open by Th15;
        then uparrow A' in the topology of S by PRE_TOPC:def 5;
        hence k in the topology of S by A2,A4,WAYBEL_0:13;
      end;
        for k being set st k in K holds x in k
      proof
        let k be set;
        assume k in K;
        then consider A being Subset of N such that
A6:       k = uparrow A and
A7:       A in J;
          y in Intersect J by YELLOW_8:def 2;
then A8:     y in A by A7,CANTOR_1:10;
          A c= uparrow A by WAYBEL_0:16;
        hence x in k by A1,A6,A8;
      end;
      hence x in Intersect K by CANTOR_1:10;
      let sA be Subset of S such that
A9:     sA is open & x in sA;
      reconsider lA = sA as Subset of N by A2;
        sigma N c= lambda N by Th10;
then A10:  sigma S c= lambda N by A2,YELLOW_9:52;
        N is Lawson correct TopAugmentation of S by A2,YELLOW_9:def 4;
      then lA is open by A9,WAYBEL19:37;
      then lA in lambda N by Th12;
      then uparrow lA in sigma S by Th14;
then A11:  uparrow lA is open by A10,Th12;
        lA c= uparrow lA by WAYBEL_0:16;
      then consider lV1 being Subset of N such that
A12:     lV1 in J and
A13:     lV1 c= uparrow lA by A1,A9,A11,YELLOW_8:def 2;
      reconsider sUV = uparrow lV1 as Subset of S by A2;
      take sUV;
      thus sUV in K by A12;
A14:  sA = uparrow sA
      proof
        thus sA c= uparrow sA by WAYBEL_0:16;
          sA is upper by A9,WAYBEL11:def 4;
        hence thesis by WAYBEL_0:24;
      end;
A15:  uparrow sA = uparrow lA by A2,WAYBEL_0:13;
        lV1 is_coarser_than uparrow lA by A13,WAYBEL12:20;
      hence sUV c= sA by A14,A15,YELLOW12:28;
    end;
    hence Z is Basis of x;
  end;

:: Proposition 2.1 (ii), p. 153
theorem Th17:
 for N being meet-continuous Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N
   for X being upper Subset of N, Y being Subset of S st X = Y
  holds Int X = Int Y
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        X be upper Subset of N,
        Y be Subset of S such that
A1:   X = Y;
A2: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
A3: Int X c= uparrow Int X by WAYBEL_0:16;
    reconsider sX = Int X as Subset of S by A2;
    reconsider K = uparrow Int X as Subset of S by A2;
      uparrow sX is open by Th15;
then A4: K is open by A2,WAYBEL_0:13;
      K c= Y
    proof
      let a be set; assume
A5:     a in K;
      then reconsider x = a as Element of N;
      consider y being Element of N such that
A6:     y <= x & y in Int X by A5,WAYBEL_0:def 16;
A7:   Int X c= X by TOPS_1:44;
        uparrow X = X
      proof
        thus uparrow X c= X by WAYBEL_0:24;
        thus thesis by WAYBEL_0:16;
      end;
      hence a in Y by A1,A6,A7,WAYBEL_0:def 16;
    end;
    then uparrow Int X c= Int Y by A4,TOPS_1:56;
    hence Int X c= Int Y by A3,XBOOLE_1:1;
    reconsider A = Int Y as Subset of N by A2;
   N is Lawson correct TopAugmentation of S by A2,YELLOW_9:def 4;
then A8: A is open by WAYBEL19:37;
      A c= X by A1,TOPS_1:44;
    hence Int Y c= Int X by A8,TOPS_1:56;
  end;

:: Proposition 2.1 (iii), p. 153
theorem
   for N being meet-continuous Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N
   for X being lower Subset of N, Y being Subset of S st X = Y
  holds Cl X = Cl Y
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        X be lower Subset of N,
        Y be Subset of S such that
A1:   X = Y;
A2: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
A4: X` = Y` by A1,A2;
    reconsider A = Cl Y as Subset of N by A2;
      (Cl X)` = (Cl X``)`
         .= Int X` by TOPS_1:def 1
         .= Int Y` by A4,Th17
         .= (Cl Y``)` by TOPS_1:def 1
         .= A` by A2;
    hence Cl X = Cl Y by TOPS_1:21;
  end;

theorem Th19:
 for M, N being complete LATTICE,
     LM being Lawson correct TopAugmentation of M,
     LN being Lawson correct TopAugmentation of N st
   InclPoset sigma N is continuous holds
  the topology of [:LM,LN qua TopSpace:] = lambda [:M,N:]
  proof
    let M, N be complete LATTICE,
        LM be Lawson correct TopAugmentation of M,
        LN be Lawson correct TopAugmentation of N such that
A1:   InclPoset sigma N is continuous;
    consider LMN being non empty Lawson correct TopAugmentation of [:M,N:];
    consider lMN being non empty lower correct TopAugmentation of [:M,N:];
    consider SMN being non empty Scott correct TopAugmentation of [:M,N:];
A2: LMN is Refinement of SMN, lMN by WAYBEL19:29;
      [:LM,LN qua TopSpace:] = the TopStruct of LMN
    proof
      consider SM being non empty Scott correct TopAugmentation of M;
      consider SN being non empty Scott correct TopAugmentation of N;
      consider lM being non empty lower correct TopAugmentation of M;
      consider lN being non empty lower correct TopAugmentation of N;
A3:   LM is Refinement of SM, lM & LN is Refinement of SN, lN by WAYBEL19:29;
A4:  the RelStr of SM = the RelStr of M & the RelStr of SN = the RelStr of N &
     the RelStr of lM = the RelStr of M & the RelStr of lN = the RelStr of N
      by YELLOW_9:def 4;
A5:   the RelStr of LM = the RelStr of M &
      the RelStr of LN = the RelStr of N by YELLOW_9:def 4;
A6:   the RelStr of LMN = the RelStr of [:M,N:] by YELLOW_9:def 4;
A7:   the carrier of [:LM,LN qua TopSpace:]
        = [:the carrier of LM,the carrier of LN:] by BORSUK_1:def 5
       .= the carrier of LMN by A5,A6,YELLOW_3:def 2;
        the TopStruct of LMN is Refinement of [:SM,SN qua TopSpace:],
                                            [:lM,lN qua TopSpace:]
      proof
          [:LM,LN qua TopSpace:]
         is Refinement of [:SM,SN qua TopSpace:],
            [:lM,lN qua TopSpace:] by A3,A4,YELLOW12:50;
        hence the carrier of the TopStruct of LMN =
          (the carrier of [:SM,SN qua TopSpace:]) \/
          (the carrier of [:lM,lN qua TopSpace:])
            by A7,YELLOW_9:def 6;
A8:     (omega LMN) \/ (sigma LMN) is prebasis of LMN by WAYBEL19:def 3;
A9:     the topology of [:lM,lN qua TopSpace:] = omega [:M,N:]
             by WAYBEL19:15
          .= omega LMN by A6,WAYBEL19:3;
A10:     the RelStr of SN = the RelStr of N by YELLOW_9:def 4
          .= the RelStr of Sigma N by YELLOW_9:def 4;
          the RelStr of SM = the RelStr of M by YELLOW_9:def 4
          .= the RelStr of Sigma M by YELLOW_9:def 4;
        then the TopStruct of SN = the TopStruct of Sigma N &
        the TopStruct of SM = the TopStruct of Sigma M by A10,WAYBEL29:17;
        then the topology of [:SM,SN qua TopSpace:]
           = the topology of [:Sigma M,(Sigma N) qua TopSpace:]
             by WAYBEL29:10
          .= sigma [:M,N:] by A1,WAYBEL29:34
          .= sigma LMN by A6,YELLOW_9:52;
        hence (the topology of [:SM,SN qua TopSpace:]) \/
         (the topology of [:lM,lN qua TopSpace:])
          is prebasis of the TopStruct of LMN by A8,A9,YELLOW12:33;
      end;
      hence thesis by A3,A4,A7,YELLOW12:49;
    end;
    then reconsider R = [:LM,LN qua TopSpace:] as Refinement of SMN, lMN
      by A2,YELLOW12:47;
      the topology of [:LM,LN qua TopSpace:] = the topology of R;
    hence thesis by WAYBEL19:34;
  end;

:: Proposition 2.2, p. 153
theorem Th20:
 for M, N being complete LATTICE,
     P being Lawson correct TopAugmentation of [:M,N:],
     Q being Lawson correct TopAugmentation of M,
     R being Lawson correct TopAugmentation of N st
   InclPoset sigma N is continuous holds
  the TopStruct of P = [:Q,R qua TopSpace:]
  proof
    let M, N be complete LATTICE,
        P be Lawson correct TopAugmentation of [:M,N:],
        Q be Lawson correct TopAugmentation of M,
        R be Lawson correct TopAugmentation of N such that
A1:   InclPoset sigma N is continuous;
A2: the RelStr of P = the RelStr of [:M,N:] &
    the RelStr of Q = the RelStr of M &
    the RelStr of R = the RelStr of N by YELLOW_9:def 4;
then A3: the carrier of P = [:the carrier of Q, the carrier of N:] by YELLOW_3:
def 2

      .= the carrier of [:Q,R qua TopSpace:] by A2,BORSUK_1:def 5;
      the topology of P = lambda [:M,N:] by WAYBEL19:def 4
      .= the topology of [:Q,R qua TopSpace:] by A1,Th19;
    hence the TopStruct of P = [:Q,R qua TopSpace:] by A3;
  end;

:: Theorem 2.3, p. 153, first conjunct
theorem Th21:
 for N being meet-continuous Lawson (complete TopLattice),
     x being Element of N
  holds x"/\" is continuous
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        x be Element of N;
      for X being non empty Subset of N holds x"/\" preserves_inf_of X
     by YELLOW13:11;
    hence x"/\" is continuous by WAYBEL21:45;
  end;

definition let N be meet-continuous Lawson (complete TopLattice),
               x be Element of N;
 cluster x"/\" -> continuous;
coherence by Th21;
end;

:: Theorem 2.3, p. 153, second conjunct
theorem Th22:
 for N being meet-continuous Lawson (complete TopLattice)
  st InclPoset sigma N is continuous holds N is topological_semilattice
  proof
    let N be meet-continuous Lawson (complete TopLattice) such that
A1:   InclPoset sigma N is continuous;
    let g be map of [:N,N qua TopSpace:], N such that
A2:   g = inf_op N;
    consider NN being Lawson correct TopAugmentation of [:N,N:];
A3: the RelStr of NN = the RelStr of [:N,N:] by YELLOW_9:def 4;
    then reconsider h = inf_op N as map of NN, N;
A4: the RelStr of N = the RelStr of N;
A5: h is infs-preserving
    proof
      let X be Subset of NN;
      reconsider X1 = X as Subset of [:N,N:] by A3;
        inf_op N preserves_inf_of X1 by WAYBEL_0:def 32;
      hence h preserves_inf_of X by A3,A4,WAYBEL_0:65;
    end;
then A6: h is SemilatticeHomomorphism of NN, N by WAYBEL21:5;
      h is directed-sups-preserving
    proof
      let X be Subset of NN;
      assume X is non empty directed;
      then reconsider X1 = X as non empty directed Subset of [:N,N:]
        by A3,WAYBEL_0:3;
        inf_op N preserves_sup_of X1 by WAYBEL_0:def 37;
      hence h preserves_sup_of X by A3,A4,WAYBEL_0:65;
    end;
then A7: h is continuous by A5,A6,WAYBEL21:46;
A8: the TopStruct of N = the TopStruct of N;
      N is TopAugmentation of N by YELLOW_9:44;
    then the TopStruct of NN = [:N,N qua TopSpace:] by A1,Th20;
    hence g is continuous by A2,A7,A8,YELLOW12:36;
  end;

Lm3:
now
  let S, T, x1, x2 be set such that
A1:  x1 in S & x2 in T;
A2:dom <:pr2(S,T),pr1(S,T):>
        = dom pr2(S,T) /\ dom pr1(S,T) by FUNCT_3:def 8
       .= dom pr2(S,T) /\ [:S,T:] by FUNCT_3:def 5
       .= [:S,T:] /\ [:S,T:] by FUNCT_3:def 6
       .= [:S,T:];
    [x1,x2] in [:S,T:] by A1,ZFMISC_1:106;
  hence <:pr2(S,T),pr1(S,T):>. [x1,x2]
     = [pr2(S,T). [x1,x2],pr1(S,T). [x1,x2]] by A2,FUNCT_3:def 8
    .= [x2,pr1(S,T). [x1,x2]] by A1,FUNCT_3:def 6
    .= [x2,x1] by A1,FUNCT_3:def 5;
end;

:: Proposition 2.4, p. 153
theorem
   for N being meet-continuous Lawson (complete TopLattice)
  st InclPoset sigma N is continuous holds
 N is Hausdorff iff
  for X being Subset of [:N,N qua TopSpace:] st
   X = the InternalRel of N holds X is closed
  proof
    let N be meet-continuous Lawson (complete TopLattice) such that
A1:   InclPoset sigma N is continuous;
A2: [:the carrier of N,the carrier of N:]
       = the carrier of [:N,N qua TopSpace:] by BORSUK_1:def 5;
    hereby
      assume
A3:     N is Hausdorff;
      let X be Subset of [:N,N qua TopSpace:] such that
A4:    X = the InternalRel of N;
      set INF = inf_op N,
          f = <:pr1(the carrier of N,the carrier of N),INF:>;
A5:  the carrier of [:N,N:]
        = [:the carrier of N,the carrier of N:] by YELLOW_3:def 2;
   then f is Function of [:the carrier of N,the carrier of N:],
                       [:the carrier of N,the carrier of N:] by FUNCT_3:78;
      then reconsider f as map of [:N,N qua TopSpace:],
                             [:N,N qua TopSpace:]
        by A2;
A6:   for x, y being Element of N holds f. [x,y] = [x, x "/\" y]
      proof
        let x, y be Element of N;
A7:     dom (pr1(the carrier of N,the carrier of N)) =
          [:the carrier of N,the carrier of N:] by FUNCT_2:def 1;
A8:     dom INF = [:the carrier of N,the carrier of N:] by A5,FUNCT_2:def 1;
          [x,y] in [:the carrier of N,the carrier of N:] by ZFMISC_1:106;
        hence f. [x,y]
         = [pr1(the carrier of N,the carrier of N). [x,y],INF. [x,y]]
            by A7,A8,FUNCT_3:69
        .= [x, INF. [x,y]] by FUNCT_3:def 5
        .= [x, x "/\" y] by WAYBEL_2:def 4;
      end;
        id the carrier of N c= [:the carrier of N,the carrier of N:]
        by RELSET_1:28;
      then reconsider D = id the carrier of N
       as Subset of [:N,N qua TopSpace:] by A2;
A9:  D is closed by A3,YELLOW12:46;
      reconsider INF as map of [:N,N qua TopSpace:], N by A2,A5;
        N is topological_semilattice by A1,Th22;
then A10:  INF is continuous by YELLOW13:def 5;
        pr1(the carrier of N,the carrier of N) is continuous map of
          [:N,N qua TopSpace:],N by YELLOW12:39;
then A11:  f is continuous by A10,YELLOW12:41;
        X = f"D
      proof
        hereby
          let a be set; assume
A12:         a in X;
          then consider s, t being set such that
A13:         s in the carrier of N & t in the carrier of N & a = [s,t]
              by A4,ZFMISC_1:def 2;
          reconsider s, t as Element of N by A13;
            s <= t by A4,A12,A13,ORDERS_1:def 9;
          then s "/\" t = s by YELLOW_0:25;
          then f. [s,t] = [s,s] by A6;
then A14:      f.a in D by A13,RELAT_1:def 10;
            dom f = the carrier of [:N,N qua TopSpace:]
            by FUNCT_2:def 1;
          then a in dom f by A2,A13,ZFMISC_1:106;
          hence a in f"D by A14,FUNCT_1:def 13;
        end;
        let a be set; assume
A15:      a in f"D;
then A16:    a in dom f & f.a in D by FUNCT_1:def 13;
        consider s, t being set such that
A17:       s in the carrier of N & t in the carrier of N & a = [s,t]
            by A2,A15,ZFMISC_1:def 2;
        reconsider s, t as Element of N by A17;
          f.a = [s, s "/\" t] by A6,A17;
        then s = s "/\" t by A16,RELAT_1:def 10;
        then s <= t by YELLOW_0:25;
        hence a in X by A4,A17,ORDERS_1:def 9;
      end;
      hence X is closed by A9,A11,PRE_TOPC:def 12;
    end;
    assume
A18:   for X being Subset of [:N,N qua TopSpace:]
        st X = the InternalRel of N holds X is closed;
A19: id the carrier of N = (the InternalRel of N) /\
 the InternalRel of N~
    proof
      thus id the carrier of N
        c= (the InternalRel of N) /\ the InternalRel of N~ by YELLOW12:22;
      thus thesis by YELLOW12:23;
    end;
      for A being Subset of [:N,N qua TopSpace:] st
     A = id the carrier of N holds A is closed
    proof
      let A be Subset of [:N,N qua TopSpace:] such that
A20:     A = id the carrier of N;
A21:  N~ = RelStr(#the carrier of N, (the InternalRel of N)~#)
        by LATTICE3:def 5;
      then reconsider X = the InternalRel of N,
                 Y = the InternalRel of N~
       as Subset of [:N,N qua TopSpace:]
         by BORSUK_1:def 5;
      reconsider X, Y as Subset of [:N,N qua TopSpace:]
       ;
      reconsider f = <:pr2(the carrier of N,the carrier of N),
                       pr1(the carrier of N,the carrier of N):> as
        continuous map of [:N,N qua TopSpace:],
                          [:N,N qua TopSpace:] by YELLOW12:42;
A22:  dom f = [:the carrier of N,the carrier of N:] by YELLOW12:4;
A23:  X is closed by A18;
A24:  f.:X = Y
      proof
        thus f.:X c= Y
        proof
          let y be set;
          assume y in f.:X;
          then consider x being set such that
A25:        x in dom f & x in X & y = f.x by FUNCT_1:def 12;
          consider x1, x2 being set such that
A26:        x1 in the carrier of N & x2 in the carrier of N & x = [x1,x2]
              by A25,ZFMISC_1:def 2;
            f.x = [x2,x1] by A26,Lm3;
          hence y in Y by A21,A25,A26,RELAT_1:def 7;
        end;
        let y be set; assume
A27:      y in Y;
        then consider y1, y2 being set such that
A28:      y1 in the carrier of N & y2 in the carrier of N & y = [y1,y2]
            by A21,ZFMISC_1:def 2;
A29:    [y2,y1] in X by A21,A27,A28,RELAT_1:def 7;
          f. [y2,y1] = y by A28,Lm3;
        hence y in f.:X by A22,A29,FUNCT_1:def 12;
      end;
        f is_homeomorphism by YELLOW12:43;
      then Y is closed by A23,A24,TOPS_2:72;
      hence A is closed by A19,A20,A23,TOPS_1:35;
    end;
    hence N is Hausdorff by YELLOW12:46;
  end;

:: Definition 2.5, p. 154
definition let N be non empty reflexive RelStr,
               X be Subset of N;
 func X^0 -> Subset of N equals :Def1:
  { u where u is Element of N : for D being non empty directed Subset of N
      st u <= sup D holds X meets D };
coherence
 proof
   defpred P[Element of N] means
    for D being non empty directed Subset of N st $1 <= sup D holds X meets D;
   thus {u where u is Element of N: P[u]} is Subset of N from RelStrSubset;
 end;
end;

definition let N be non empty reflexive antisymmetric RelStr,
               X be empty Subset of N;
 cluster X^0 -> empty;
coherence
  proof
A1: X^0 = { u where u is Element of N :
    for D being non empty directed Subset of N st u <= sup D holds X meets D
      } by Def1;
      X^0 = {}
    proof
      thus X^0 c= {}
      proof
        let a be set such that
A2:       a in X^0 and not a in {};
        consider u being Element of N such that
A3:       a = u &
          for D being non empty directed Subset of N st u <= sup D
           holds X meets D by A1,A2;
        reconsider D = {u} as non empty directed Subset of N by WAYBEL_0:5;
A4:     u <= sup D by YELLOW_0:39;
          X misses D by XBOOLE_1:65;
        hence contradiction by A3,A4;
      end;
      thus thesis by XBOOLE_1:2;
    end;
    hence thesis;
  end;
end;

theorem
   for N being non empty reflexive RelStr, A, J being Subset of N st A c= J
  holds A^0 c= J^0
  proof
    let N be non empty reflexive RelStr,
        A, J be Subset of N such that
A1:   A c= J;
A2: A^0 = { u where u is Element of N :
     for D being non empty directed Subset of N st u <= sup D
      holds A meets D } by Def1;
A3: J^0 = { u where u is Element of N :
     for D being non empty directed Subset of N st u <= sup D
      holds J meets D } by Def1;
    let a be set;
    assume a in A^0;
    then consider u being Element of N such that
A4:   a = u &
      for D being non empty directed Subset of N st u <= sup D
       holds A meets D by A2;
      now
      let D be non empty directed Subset of N;
      assume u <= sup D;
      then A meets D by A4;
      hence J meets D by A1,XBOOLE_1:63;
    end;
    hence a in J^0 by A3,A4;
  end;

:: Remark 2.6 (i), p. 154
theorem Th25:
 for N being non empty reflexive RelStr, x being Element of N holds
  (uparrow x)^0 = wayabove x
  proof
    let N be non empty reflexive RelStr,
        x be Element of N;
A1: (uparrow x)^0 =
     { u where u is Element of N : for D being non empty directed Subset of N
      st u <= sup D holds (uparrow x) meets D } by Def1;
    thus (uparrow x)^0 c= wayabove x
    proof
      let a be set;
      assume a in (uparrow x)^0;
      then consider u being Element of N such that
A2:     a = u &
        for D being non empty directed Subset of N st u <= sup D
         holds (uparrow x) meets D by A1;
         u >> x
       proof
         let D be non empty directed Subset of N; assume
          u <= sup D;
         then (uparrow x) meets D by A2;
         then consider d being set such that
A3:        d in (uparrow x) /\ D by XBOOLE_0:4;
         reconsider d as Element of N by A3;
         take d;
         thus d in D by A3,XBOOLE_0:def 3;
           d in uparrow x by A3,XBOOLE_0:def 3;
         hence x <= d by WAYBEL_0:18;
       end;
       hence a in wayabove x by A2,WAYBEL_3:8;
    end;
    let a be set; assume
A4:   a in wayabove x;
    then reconsider b = a as Element of N;
      now
      let D be non empty directed Subset of N such that
A5:     b <= sup D;
        b >> x by A4,WAYBEL_3:8;
      then consider d being Element of N such that
A6:     d in D & x <= d by A5,WAYBEL_3:def 1;
        d in uparrow x by A6,WAYBEL_0:18;
      hence (uparrow x) meets D by A6,XBOOLE_0:3;
    end;
    hence a in (uparrow x)^0 by A1;
  end;

:: Remark 2.6 (ii), p. 154
theorem Th26:
 for N being Scott TopLattice, X being upper Subset of N holds Int X c= X^0
  proof
    let N be Scott TopLattice,
        X be upper Subset of N;
    let x be set; assume
A1:   x in Int X;
    then reconsider y = x as Element of N;
A2: X^0 = { u where u is Element of N : for D being non empty directed
      Subset of N st u <= sup D holds X meets D } by Def1;
      now
      let D be non empty directed Subset of N such that
A3:     y <= sup D;
A4:   Int X c= X by TOPS_1:44;
A5:   Int X is upper inaccessible by WAYBEL11:def 4;
      then sup D in Int X by A1,A3,WAYBEL_0:def 20;
      then D meets Int X by A5,WAYBEL11:def 1;
      hence X meets D by A4,XBOOLE_1:63;
    end;
    hence x in X^0 by A2;
  end;

:: Lemma 2.7 (i), p. 154
theorem Th27:
 for N being non empty reflexive RelStr, X, Y being Subset of N holds
  (X^0) \/ (Y^0) c= (X \/ Y)^0
  proof
    let N be non empty reflexive RelStr,
        X, Y be Subset of N;
    let a be set; assume
A1:   a in (X^0) \/ (Y^0);
    then reconsider b = a as Element of N;
A2: X^0 = { x where x is Element of N : for D being non empty directed
     Subset of N st x <= sup D holds X meets D } by Def1;
A3: Y^0 = { y where y is Element of N : for D being non empty directed
     Subset of N st y <= sup D holds Y meets D } by Def1;
A4: (X \/ Y)^0 = { xy where xy is Element of N :
     for D being non empty directed Subset of N st xy <= sup D
      holds (X \/ Y) meets D } by Def1;
      now
      let D be non empty directed Subset of N such that
A5:     b <= sup D;
        now per cases by A1,XBOOLE_0:def 2;
      suppose a in X^0;
      then consider x being Element of N such that
A6:     a = x &
        for D being non empty directed Subset of N st x <= sup D
          holds X meets D by A2;
     X meets D by A5,A6;
then A7:    X /\ D <> {} by XBOOLE_0:def 7;
        X /\ D c= X /\ D \/ Y /\ D by XBOOLE_1:7;
      then X /\ D \/ Y /\ D <> {} by A7,XBOOLE_1:3;
      hence (X \/ Y) /\ D <> {} by XBOOLE_1:23;
      suppose a in Y^0;
      then consider y being Element of N such that
A8:     a = y &
        for D being non empty directed Subset of N st y <= sup D
          holds Y meets D by A3;
     Y meets D by A5,A8;
then A9:    Y /\ D <> {} by XBOOLE_0:def 7;
        Y /\ D c= X /\ D \/ Y /\ D by XBOOLE_1:7;
      then X /\ D \/ Y /\ D <> {} by A9,XBOOLE_1:3;
      hence (X \/ Y) /\ D <> {} by XBOOLE_1:23;
      end;
      hence (X \/ Y) meets D by XBOOLE_0:def 7;
    end;
    hence a in (X \/ Y)^0 by A4;
  end;

:: Lemma 2.7 (ii), p. 154
theorem Th28:
 for N being meet-continuous LATTICE, X, Y being upper Subset of N holds
  (X^0) \/ (Y^0) = (X \/ Y)^0
  proof
    let N be meet-continuous LATTICE,
        X, Y be upper Subset of N;
    thus (X^0) \/ (Y^0) c= (X \/ Y)^0 by Th27;
    assume not (X \/ Y)^0 c= (X^0) \/ (Y^0);
    then consider s being set such that
A1:   s in (X \/ Y)^0 and
A2:   not s in (X^0) \/ (Y^0) by TARSKI:def 3;
A3: not s in X^0 & not s in Y^0 by A2,XBOOLE_0:def 2;
    reconsider s as Element of N by A1;
      X^0 = { x where x is Element of N :
     for D being non empty directed Subset of N st x <= sup D holds
      X meets D } by Def1;
    then consider D being non empty directed Subset of N such that
A4:   s <= sup D & X misses D by A3;
      Y^0 = { y where y is Element of N :
     for D being non empty directed Subset of N st y <= sup D holds
       Y meets D } by Def1;
    then consider E being non empty directed Subset of N such that
A5:   s <= sup E & Y misses E by A3;
      (X \/ Y)^0 = { xy where xy is Element of N :
     for D being non empty directed Subset of N st xy <= sup D
      holds (X \/ Y) meets D } by Def1;
    then consider xy being Element of N such that
A6:  s = xy & for D being non empty directed Subset of N st xy <= sup D
       holds (X \/ Y) meets D by A1;
      s "/\" s = s by YELLOW_0:25;
    then s <= (sup D) "/\" (sup E) by A4,A5,YELLOW_3:2;
    then s <= sup (D "/\" E) by WAYBEL_2:51;
 then (X \/ Y) meets (D"/\"E) by A6;
then A7:  (X \/ Y) /\ (D"/\"E) <> {} by XBOOLE_0:def 7;
      X misses (D "/\" E) & Y misses (D "/\" E) by A4,A5,YELLOW12:21;
    then X /\ (D "/\" E) = {} & Y /\ (D "/\" E) = {} by XBOOLE_0:def 7;
    then X /\ (D"/\"E) \/ Y /\ (D"/\"E) = {};
    hence contradiction by A7,XBOOLE_1:23;
  end;

:: Lemma 2.8, p. 154
theorem Th29:
 for S being meet-continuous Scott TopLattice, F being finite Subset of S holds
  Int uparrow F c= union { wayabove x where x is Element of S : x in F }
  proof
    let S be meet-continuous Scott TopLattice,
        F be finite Subset of S;
defpred P[set] means
ex UU being Subset-Family of S st
 UU = {uparrow x where x is Element of S : x in $1} &
  (union UU)^0 = union { (uparrow x)^0 where x is Element of S : x in $1 };

A1: F is finite;
A2: P[{}]
    proof
        {} is Subset of bool the carrier of S by XBOOLE_1:2;
      then {} is Subset-Family of S by SETFAM_1:def 7;
      then reconsider UU = {} as Subset-Family of S;
      take UU;
      thus UU = {uparrow x where x is Element of S : x in {}}
      proof deffunc F(Element of S) = uparrow $1;
          {F(x) where x is Element of S : x in {}} = {} from EmptySch;
        hence thesis;
      end;
       deffunc F(Element of S) = (uparrow $1)^0;
A3:   {F(x) where x is Element of S : x in {}} = {} from EmptySch;
      reconsider K = union UU as empty Subset of S by ZFMISC_1:2;
        K^0 is empty;
      hence thesis by A3;
    end;
A4: for b, J being set st b in F & J c= F & P[J] holds P[J \/ {b}]
    proof
      let b, J be set; assume
A5:     b in F & J c= F;
      assume P[J];

      then consider UU being Subset-Family of S such that
A6:     UU = {uparrow x where x is Element of S : x in J} and
A7:     (union UU)^0 = union {(uparrow x)^0 where x is Element of S : x in J};

      reconsider bb = b as Element of S by A5;
        UU \/ {uparrow bb} is Subset-Family of S
      proof
          UU \/ {uparrow bb} c= bool the carrier of S
        proof
          let a be set;
          assume a in UU \/ {uparrow bb};
          then a in UU or a in {uparrow bb} by XBOOLE_0:def 2;
          then a in UU or a = uparrow bb by TARSKI:def 1;
          hence a in bool the carrier of S;
        end;
        hence thesis by SETFAM_1:def 7;
      end;
      then reconsider I = UU \/ {uparrow bb} as Subset-Family of S
       ;
      take I;
      thus I = {uparrow x where x is Element of S : x in J \/ {b}}
      proof
        thus I c= {uparrow x where x is Element of S : x in J \/ {b}}
        proof
          let a be set such that
A8:         a in I;
          per cases by A8,XBOOLE_0:def 2;
          suppose a in UU;
          then consider x being Element of S such that
A9:         a = uparrow x & x in J by A6;
            J c= J \/ {b} by XBOOLE_1:7;
          hence thesis by A9;
          suppose a in {uparrow bb};
then A10:       a = uparrow bb by TARSKI:def 1;
            b in {b} & {b} c= J \/ {b} by TARSKI:def 1,XBOOLE_1:7;
          hence thesis by A10;
        end;
        let a be set;
        assume a in {uparrow x where x is Element of S : x in J \/ {b}};
        then consider x being Element of S such that
A11:       a = uparrow x & x in J \/ {b};
        per cases by A11,XBOOLE_0:def 2;
        suppose x in J;
then A12:     uparrow x in UU by A6;
          UU c= UU \/ {uparrow bb} by XBOOLE_1:7;
        hence thesis by A11,A12;
        suppose x in {b};
then A13:     x = b by TARSKI:def 1;
A14:     a in {uparrow x} by A11,TARSKI:def 1;
          {uparrow bb} c= UU \/ {uparrow bb} by XBOOLE_1:7;
        hence thesis by A13,A14;
      end;
        for X being Subset of S st X in UU holds X is upper
      proof
        let X be Subset of S;
        assume X in UU;
        then consider x being Element of S such that
A15:       X = uparrow x & x in J by A6;
        thus X is upper by A15;
      end;
then A16:   union UU is upper by WAYBEL_0:28;
A17:   (union UU) \/ uparrow bb = union I
      proof
        thus (union UU) \/ uparrow bb c= union I
        proof
          let a be set such that
A18:         a in (union UU) \/ uparrow bb;
          per cases by A18,XBOOLE_0:def 2;
          suppose a in union UU;
          then consider A being set such that
A19:         a in A & A in UU by TARSKI:def 4;
            UU c= I by XBOOLE_1:7;
          hence a in union I by A19,TARSKI:def 4;
          suppose
A20:         a in uparrow bb;
A21:       {uparrow bb} c= UU \/ {uparrow bb} by XBOOLE_1:7;
            uparrow bb in {uparrow bb} by TARSKI:def 1;
          hence a in union I by A20,A21,TARSKI:def 4;
        end;
        let a be set;
        assume a in union I;
        then consider A being set such that
A22:       a in A & A in I by TARSKI:def 4;
        per cases by A22,XBOOLE_0:def 2;
        suppose A in UU;
        then A c= union UU by ZFMISC_1:92;
then A23:     a in union UU by A22;
          union UU c= (union UU) \/ uparrow bb by XBOOLE_1:7;
        hence a in (union UU) \/ uparrow bb by A23;
        suppose A in {uparrow bb};
then A24:     A = uparrow bb by TARSKI:def 1;
          uparrow bb c= (union UU) \/ uparrow bb by XBOOLE_1:7;
        hence a in (union UU) \/ uparrow bb by A22,A24;
      end;
        (union {(uparrow x)^0 where x is Element of S : x in J}) \/
       ((uparrow bb)^0) =
          union {(uparrow x)^0 where x is Element of S : x in J \/ {b}}
      proof
          {(uparrow x)^0 where x is Element of S : x in J} c=
          {(uparrow x)^0 where x is Element of S : x in J \/ {b}}
        proof
          let a be set;
          assume a in {(uparrow x)^0 where x is Element of S : x in J};
          then consider y being Element of S such that
A25:         a = (uparrow y)^0 & y in J;
            J c= J \/ {b} by XBOOLE_1:7;
          hence a in {(uparrow x)^0 where x is Element of S : x in J \/ {b}}
            by A25;
        end;
then A26:     union {(uparrow x)^0 where x is Element of S : x in J} c=
          union {(uparrow x)^0 where x is Element of S : x in J \/ {b}}
           by ZFMISC_1:95;
A27:     b in {b} by TARSKI:def 1;
          {b} c= J \/ {b} by XBOOLE_1:7;
        then (uparrow bb)^0 in {(uparrow x)^0 where x is Element of S : x in
 J \/ {b}}
          by A27;
        then (uparrow bb)^0 c=
          union {(uparrow x)^0 where x is Element of S : x in J \/ {b}}
           by ZFMISC_1:92;
        hence (union {(uparrow x)^0 where x is Element of S : x in J}) \/
         ((uparrow bb)^0) c=
          union {(uparrow x)^0 where x is Element of S : x in J \/ {b}}
          by A26,XBOOLE_1:8;
        let a be set;
        assume a in union {(uparrow x)^0 where x is Element of S : x in
 J \/ {b}};
      then consider A being set such that
A28:       a in A & A in {(uparrow x)^0 where x is Element of S : x in J \/
 {b}}
            by TARSKI:def 4;
        consider y being Element of S such that
A29:       A = (uparrow y)^0 & y in J \/ {b} by A28;
        per cases by A29,XBOOLE_0:def 2;
        suppose y in J;
        then (uparrow y)^0 in {(uparrow x)^0 where x is Element of S : x in J}
;
then A30:     a in union {(uparrow x)^0 where x is Element of S : x in J}
          by A28,A29,TARSKI:def 4;
          union {(uparrow x)^0 where x is Element of S : x in J} c=
         (union {(uparrow x)^0 where x is Element of S : x in J}) \/
          ((uparrow bb)^0) by XBOOLE_1:7;
        hence thesis by A30;
        suppose y in {b};
then A31:     y = b by TARSKI:def 1;
          (uparrow bb)^0 c= (union {(uparrow x)^0 where x is Element of S :
          x in J}) \/ ((uparrow bb)^0) by XBOOLE_1:7;
        hence thesis by A28,A29,A31;
      end;
      hence (union I)^0 = union { (uparrow x)^0 where x is Element of S :
        x in J \/ {b} } by A7,A16,A17,Th28;
    end;
    P[F] from Finite(A1,A2,A4);
    then consider UU being Subset-Family of S such that
A32:  UU = {uparrow x where x is Element of S : x in F} &
     (union UU)^0 = union { (uparrow x)^0 where x is Element of S : x in F };
  {(uparrow x)^0 where x is Element of S : x in F} =
      {wayabove x where x is Element of S : x in F}
    proof
      thus {(uparrow x)^0 where x is Element of S : x in F} c=
        {wayabove x where x is Element of S : x in F}
      proof
        let a be set;
        assume a in {(uparrow x)^0 where x is Element of S : x in F};
        then consider x being Element of S such that
A33:       a = (uparrow x)^0 & x in F;
          (uparrow x)^0 = wayabove x by Th25;
        hence thesis by A33;
      end;
      let a be set;
      assume a in {wayabove x where x is Element of S : x in F};
      then consider x being Element of S such that
A34:     a = wayabove x & x in F;
        (uparrow x)^0 = wayabove x by Th25;
      hence thesis by A34;
    end;
    then (uparrow F)^0 = union {wayabove x where x is Element of S : x in F}
         by A32,YELLOW_9:4;
    hence Int uparrow F c= union {wayabove x where x is Element of S : x in F}
      by Th26;
  end;

:: Theorem 2.9, p. 154
theorem Th30:
 for N being Lawson (complete TopLattice)
  holds N is continuous iff N is meet-continuous Hausdorff
  proof
    let N be Lawson (complete TopLattice);
    hereby
      assume N is continuous;
      then reconsider L1 = N as continuous lower-bounded Lawson
       (complete TopLattice);
        L1 is meet-continuous;
      hence N is meet-continuous Hausdorff;
    end;
    assume
A1:   N is meet-continuous Hausdorff;
    thus
A2:   for x being Element of N holds waybelow x is non empty directed;
    thus N is up-complete;
      for x, y being Element of N st not x <= y
     ex u being Element of N st u << x & not u <= y
    proof
      let x, y be Element of N such that
A3:     not x <= y;
      consider S being Scott TopAugmentation of N;
A4:   the RelStr of S = the RelStr of N by YELLOW_9:def 4;
      reconsider J =
       {O\uparrow F where O, F is Subset of N: O in sigma N & F is finite}
        as Basis of N by WAYBEL19:32;
        x "/\" y <> x by A3,YELLOW_0:23;
      then consider W, V being Subset of N such that
A5:     W is open and
A6:     V is open and
A7:     x in W & x "/\" y in V & W misses V by A1,COMPTS_1:def 4;
        V = union {G where G is Subset of N: G in J & G c= V} by A6,YELLOW_8:18
;
      then consider K being set such that
A8:     x "/\" y in K & K in {G where G is Subset of N: G in J & G c= V}
          by A7,TARSKI:def 4;
      consider V1 being Subset of N such that
A9:     K = V1 & V1 in J & V1 c= V by A8;
      consider U2, F being Subset of N such that
A10:     V1 = U2\uparrow F and
A11:     U2 in sigma N and
A12:     F is finite by A9;
      reconsider U1 = U2 as Subset of S by A4;
        U2 in sigma S by A4,A11,YELLOW_9:52;
then A13:   U1 is open by WAYBEL14:24;
      reconsider WU1 = W /\ U2 as Subset of N;
        WU1 c= uparrow F
      proof
        let w be set; assume
A14:       w in WU1 & not w in uparrow F;
then A15:     w in W by XBOOLE_0:def 3;
A16:     w in WU1 \ uparrow F by A14,XBOOLE_0:def 4;
A17:     W misses V1 by A7,A9,XBOOLE_1:63;
          W /\ U1 c= U1 by XBOOLE_1:17;
        then WU1 \ uparrow F c= U1 \ uparrow F by XBOOLE_1:33;
        hence contradiction by A10,A15,A16,A17,XBOOLE_0:3;
      end;
      then WU1 is_coarser_than uparrow F by WAYBEL12:20;
then A18:  uparrow WU1 c= uparrow F by YELLOW12:28;
      reconsider W1 = WU1 as Subset of S by A4;
      reconsider F1 = F as finite Subset of S by A4,A12;
        S is meet-continuous by A1,A4,YELLOW12:14;
then A19:   Int uparrow F1 c=
        union { wayabove u where u is Element of S : u in F1 } by Th29;
A20:   uparrow W1 = uparrow WU1 & uparrow F1 = uparrow F
        by A4,WAYBEL_0:13;
      reconsider x1 = x, y1 = y as Element of S by A4;
A21:   ex_inf_of {x1,y1},S by YELLOW_0:21;
        x "/\" y = inf {x,y} by YELLOW_0:40
            .= "/\"({x1,y1},S) by A4,A21,YELLOW_0:27
            .= x1 "/\" y1 by YELLOW_0:40;
then A22:   x1 "/\" y1 in U1 by A8,A9,A10,XBOOLE_0:def 4;
A23:   x1 "/\" y1 <= x1 by YELLOW_0:23;
        U1 is upper by A13,WAYBEL11:def 4;
      then x1 in U1 by A22,A23,WAYBEL_0:def 20;
then A24:   x in W1 by A7,XBOOLE_0:def 3;
        W1 c= uparrow W1 by WAYBEL_0:16;
then A25:  x in uparrow W1 by A24;
        N is Lawson correct TopAugmentation of S by A4,YELLOW_9:def 4;
      then U2 is open by A13,WAYBEL19:37;
      then WU1 is open by A5,TOPS_1:38;
      then uparrow W1 is open by A1,Th15;
      then uparrow W1 c= Int uparrow F1 by A18,A20,TOPS_1:56;
      then x in Int uparrow F1 by A25;
      then consider A being set such that
A26:    x in A & A in { wayabove u where u is Element of S : u in F1 }
         by A19,TARSKI:def 4;
      consider u being Element of S such that
A27:     A = wayabove u & u in F1 by A26;
      reconsider u1 = u as Element of N by A4;
A28:  wayabove u1 = wayabove u by A4,YELLOW12:13;
A29:   for N being Semilattice, x, y being Element of N st
       ex u being Element of N st u << x & not u <= x "/\" y
        ex u being Element of N st u << x & not u <= y
      proof
        let N be Semilattice,
            x, y be Element of N;
        given u being Element of N such that
A30:       u << x and
A31:       not u <= x "/\" y;
        take u;
        thus u << x by A30;
        assume
A32:       u <= y;
          u <= x by A30,WAYBEL_3:1;
        then u "/\" u <= x "/\" y by A32,YELLOW_3:2;
        hence contradiction by A31,YELLOW_0:25;
      end;
        now
        take u1;
        thus u1 << x by A26,A27,A28,WAYBEL_3:8;
          uparrow u1 c= uparrow F by A27,YELLOW12:30;
        then not x "/\" y in uparrow u1 by A8,A9,A10,XBOOLE_0:def 4;
        hence not u1 <= x "/\" y by WAYBEL_0:18;
      end;
      then consider u2 being Element of N such that
A33:    u2 << x & not u2 <= y by A29;
      take u2;
      thus thesis by A33;
    end;
    hence N is satisfying_axiom_of_approximation by A2,WAYBEL_3:24;
  end;

definition
 cluster continuous Lawson -> Hausdorff (complete TopLattice);
coherence by Th30;
 cluster meet-continuous Lawson Hausdorff -> continuous (complete TopLattice);
coherence by Th30;
end;

:: Definition 2.10, p. 155
definition let N be non empty TopRelStr;
 attr N is with_small_semilattices means
    for x being Point of N ex J being basis of x st
   for A being Subset of N st A in J holds subrelstr A is meet-inheriting;
 attr N is with_compact_semilattices means
    for x being Point of N ex J being basis of x st
   for A being Subset of N st A in J holds subrelstr A is meet-inheriting &
    A is compact;
 attr N is with_open_semilattices means :Def4:
  for x being Point of N ex J being Basis of x st
   for A being Subset of N st A in J holds subrelstr A is meet-inheriting;
end;

definition
 cluster with_open_semilattices -> with_small_semilattices
                                   (non empty TopSpace-like TopRelStr);
coherence
  proof
    let N be non empty TopSpace-like TopRelStr;
    assume
A1:   for x being Point of N ex J being Basis of x st
     for A being Subset of N st A in J holds subrelstr A is meet-inheriting;
    let x be Point of N;
    consider J being Basis of x such that
A2:   for A being Subset of N st A in J holds subrelstr A is meet-inheriting
        by A1;
    reconsider J as basis of x by YELLOW13:23;
    take J;
    thus thesis by A2;
  end;

 cluster with_compact_semilattices -> with_small_semilattices
                                      (non empty TopSpace-like TopRelStr);
coherence
  proof
    let N be non empty TopSpace-like TopRelStr;
    assume
A3:  for x being Point of N ex J being basis of x st
      for A being Subset of N st A in J holds subrelstr A is meet-inheriting &
       A is compact;
    let x be Point of N;
    consider J being basis of x such that
A4:   for A being Subset of N st A in J holds subrelstr A is meet-inheriting
        & A is compact by A3;
    take J;
    thus thesis by A4;
  end;

 cluster anti-discrete -> with_small_semilattices with_open_semilattices
                                                   (non empty TopRelStr);
coherence
  proof
    let T be non empty TopRelStr;
    assume T is anti-discrete;
    then reconsider W = T as anti-discrete non empty TopRelStr;
    set J = {the carrier of W};
A5: now
      let A be Subset of W;
      assume A in J;
then A6:   A = the carrier of W by TARSKI:def 1
       .= [#]W by PRE_TOPC:12;
        subrelstr [#]W is infs-inheriting;
      then reconsider K = subrelstr A as infs-inheriting SubRelStr of T by A6;
        K is meet-inheriting;
      hence subrelstr A is meet-inheriting;
    end;
A7: W is with_small_semilattices
    proof
      let x be Point of W;
      reconsider J as basis of x by YELLOW13:21;
      take J;
      let A be Subset of W;
      assume A in J;
      hence subrelstr A is meet-inheriting by A5;
    end;
      W is with_open_semilattices
    proof
      let x be Point of W;
      reconsider J as Basis of x by YELLOW13:13;
      take J;
      let A be Subset of W;
      assume A in J;
      hence subrelstr A is meet-inheriting by A5;
    end;
    hence thesis by A7;
  end;

 cluster reflexive trivial TopSpace-like ->
                             with_compact_semilattices (non empty TopRelStr);
coherence
  proof
    let T be non empty TopRelStr;
    assume T is reflexive trivial TopSpace-like;
    then reconsider W = T as reflexive trivial non empty TopSpace-like
TopRelStr;
      W is with_compact_semilattices
    proof
      let x be Point of W;
      reconsider J = {the carrier of W} as basis of x by YELLOW13:21;
      take J;
      let A be Subset of W;
      assume A in J;
then A8:   A = the carrier of W by TARSKI:def 1
       .= [#]W by PRE_TOPC:12;
        subrelstr [#]W is infs-inheriting;
      then reconsider K = subrelstr A as infs-inheriting SubRelStr of T by A8;
        K is meet-inheriting;
      hence subrelstr A is meet-inheriting;
      thus A is compact by A8;
    end;
    hence thesis;
  end;
end;

definition
 cluster strict trivial lower TopLattice;
existence
  proof
    consider T being strict trivial TopLattice;
    take T;
    thus thesis;
  end;
end;

theorem Th31:
 for N being topological_semilattice (with_infima TopPoset),
     C being Subset of N st subrelstr C is meet-inheriting holds
  subrelstr Cl C is meet-inheriting
  proof
    let N be topological_semilattice (with_infima TopPoset),
        C be Subset of N such that
A1:   subrelstr C is meet-inheriting;
    set A = Cl C,
        S = subrelstr A;
    let x, y be Element of N such that
A2:  x in the carrier of S & y in the carrier of S & ex_inf_of {x,y},N;
A3: the carrier of S = A by YELLOW_0:def 15;
      for V being a_neighborhood of x "/\" y holds V meets C
    proof
      let V be a_neighborhood of x "/\" y;
      set NN = [:N,N qua TopSpace:];
A4:   the carrier of NN = [:the carrier of N,the carrier of N:]
        by BORSUK_1:def 5;
        the carrier of [:N,N:] = [:the carrier of N,the carrier of N:]
        by YELLOW_3:def 2;
      then reconsider f = inf_op N as map of NN, N by A4;
A5:   f is continuous by YELLOW13:def 5;
      reconsider xy = [x,y] as Point of NN by A4,YELLOW_3:def 2;
        f.xy = x "/\" y by WAYBEL_2:def 4;
      then consider H being a_neighborhood of xy such that
A6:     f.:H c= V by A5,BORSUK_1:def 2;
      consider A being Subset-Family of NN such that
A7:     Int H = union A and
A8:     for e being set st e in A ex X1, Y1 being Subset of N
         st e = [:X1,Y1:] & X1 is open & Y1 is open by BORSUK_1:45;
        xy in union A by A7,CONNSP_2:def 1;
      then consider K being set such that
A9:     xy in K and
A10:    K in A by TARSKI:def 4;
      consider Ix, Iy being Subset of N such that
A11:    K = [:Ix,Iy:] & Ix is open & Iy is open by A8,A10;
        x in Ix & Ix = Int Ix by A9,A11,TOPS_1:55,ZFMISC_1:106;
      then reconsider Ix as a_neighborhood of x by CONNSP_2:def 1;
        Ix meets C by A2,A3,YELLOW_6:6;
      then consider ix being set such that
A12:    ix in Ix & ix in C by XBOOLE_0:3;
        y in Iy & Iy = Int Iy by A9,A11,TOPS_1:55,ZFMISC_1:106;
      then reconsider Iy as a_neighborhood of y by CONNSP_2:def 1;
        Iy meets C by A2,A3,YELLOW_6:6;
      then consider iy being set such that
A13:    iy in Iy & iy in C by XBOOLE_0:3;
      reconsider ix, iy as Element of N by A12,A13;
        now take a = ix "/\" iy;
A14:  f. [ix,iy] = ix "/\" iy by WAYBEL_2:def 4;
A15:  dom f = the carrier of [:N,N:] by FUNCT_2:def 1;
        [ix,iy] in K by A11,A12,A13,ZFMISC_1:106;
then A16:  [ix,iy] in Int H by A7,A10,TARSKI:def 4;
        Int H c= H by TOPS_1:44;
      then ix "/\" iy in f.:H by A14,A15,A16,FUNCT_1:def 12;
      hence a in V by A6;
A17:  the carrier of subrelstr C = C by YELLOW_0:def 15;
        ex_inf_of {ix,iy},N by YELLOW_0:21;
      then inf{ix,iy} in C by A1,A12,A13,A17,YELLOW_0:def 16;
      hence a in C by YELLOW_0:40;
     end; hence thesis by XBOOLE_0:3;
    end;
    then x "/\" y in Cl C by YELLOW_6:6;
    hence inf {x,y} in the carrier of S by A3,YELLOW_0:40;
  end;

:: Theorem 2.11, p. 155
theorem Th32:
 for N being meet-continuous Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N holds
  (for x being Point of S ex J being Basis of x st
   for W being Subset of S st W in J holds W is Filter of S) iff
  N is with_open_semilattices
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N;
A1: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    hereby assume
A2:   for x being Point of S ex J being Basis of x st
       for W being Subset of S st W in J holds W is Filter of S;
      thus N is with_open_semilattices
      proof
        let x be Point of N;
A3:     now
          let W be Subset of N such that
A4:         W is open and
A5:         x in W;
          reconsider BL =
          {O\uparrow F where O, F is Subset of N: O in sigma N & F is finite}
           as Basis of N by WAYBEL19:32;
          reconsider y = x as Point of S by A1;
          consider By being Basis of y such that
A6:         for A being Subset of S st A in By holds A is Filter of S by A2;

            W = union { G where G is Subset of N: G in BL & G c= W }
            by A4,YELLOW_8:18;
          then consider K being set such that
A7:         x in K & K in { G where G is Subset of N: G in BL & G c= W }
             by A5,TARSKI:def 4;
          consider G being Subset of N such that
A8:         K = G and
A9:         G in BL and
A10:         G c= W by A7;
          consider V, F being Subset of N such that
A11:         G = V \ uparrow F and
A12:         V in sigma N and
A13:         F is finite by A9;
          reconsider V as Subset of S by A1;
A14:       sigma N = sigma S by A1,YELLOW_9:52;
then A15:       V is open by A12,WAYBEL14:24;
          reconsider F as finite Subset of N by A13;
            y in V by A7,A8,A11,XBOOLE_0:def 4;
          then consider U1 being Subset of S such that
A16:         U1 in By and
A17:         U1 c= V by A15,YELLOW_8:22;
          reconsider U2 = U1 as Subset of N by A1;
            U1 is Filter of S by A6,A16;
          then reconsider U2 as Filter of N by A1,WAYBEL_0:4,25;
            U2 \ uparrow F is Subset of N;
          then reconsider IT = U1 \ uparrow F as Subset of N;

          take U2, F, IT;

          thus IT = U2 \ uparrow F;
A18:       y in U1 by A16,YELLOW_8:21;
            not x in uparrow F by A7,A8,A11,XBOOLE_0:def 4;
          hence x in IT by A18,XBOOLE_0:def 4;
            U1 is open by A16,YELLOW_8:21;
          then U1 in sigma S by WAYBEL14:24;
then A19:      IT in BL by A14;
            BL c= the topology of N by CANTOR_1:def 2;
          hence IT is open by A19,PRE_TOPC:def 5;
            IT c= G by A11,A17,XBOOLE_1:33;
          hence IT c= W by A10,XBOOLE_1:1;
        end;

        defpred P[set] means
          ex U1 being Filter of N, F being finite Subset of N,
             W1 being Subset of N st $1 = W1 &
           U1 \ uparrow F = $1 & x in $1 & W1 is open;
        consider SF being Subset-Family of N such that
A20:      for W being Subset of N holds W in SF iff P[W]
            from SubFamEx;

        reconsider SF as Subset-Family of N;
          SF is Basis of x
        proof
          thus SF c= the topology of N
          proof
            let a be set; assume
A21:           a in SF;
            then reconsider W = a as Subset of N;
            consider U1 being Filter of N,
                     F being finite Subset of N,
                     W1 being Subset of N such that
A22:          W1 = W and
                U1 \ uparrow F = W & x in W and
A23:           W1 is open by A20,A21;
            thus thesis by A22,A23,PRE_TOPC:def 5;
          end;
            for a being set st a in SF holds x in a
          proof
            let a be set; assume
A24:           a in SF;
            then reconsider W = a as Subset of N;
            consider U1 being Filter of N,
                     F being finite Subset of N,
                     W1 being Subset of N such that
A25:           W1 = W & U1 \ uparrow F = W & x in W & W1 is open by A20,A24;
            thus x in a by A25;
          end;
          hence x in Intersect SF by CANTOR_1:10;
          let W be Subset of N;
          assume W is open & x in W;
          then consider U2 being Filter of N,
                   F being finite Subset of N,
                   IT being Subset of N such that
A26:         IT = U2 \ uparrow F & x in IT & IT is open & IT c= W by A3;
          take IT;
          thus IT in SF & IT c= W by A20,A26;
        end;
        then reconsider SF as Basis of x;
        take SF;
        let W be Subset of N;
        assume W in SF;
        then consider U1 being Filter of N,
                 F being finite Subset of N,
                 W1 being Subset of N such that
A27:       W1 = W & U1 \ uparrow F = W & x in W & W1 is open by A20;
        set SW = subrelstr W;
        thus SW is meet-inheriting
        proof
          let a, b be Element of N such that
A28:         a in the carrier of SW & b in the carrier of SW &
              ex_inf_of {a,b},N;
A29:       the carrier of SW = W by YELLOW_0:def 15;
then A30:       a in U1 & b in U1 & not a in uparrow F & not b in uparrow F
            by A27,A28,XBOOLE_0:def 4;
          then consider z being Element of N such that
A31:         z in U1 & z <= a & z <= b by WAYBEL_0:def 2;
            z "/\" z <= a "/\" b by A31,YELLOW_3:2;
          then z <= a "/\" b by YELLOW_0:25;
then A32:       a "/\" b in U1 by A31,WAYBEL_0:def 20;
            for y being Element of N st y <= a "/\" b holds not y in F
          proof
            let y be Element of N such that
A33:           y <= a "/\" b;
              a "/\" b <= a by YELLOW_0:23;
            then y <= a by A33,ORDERS_1:26;
            hence not y in F by A30,WAYBEL_0:def 16;
          end;
          then not a "/\" b in uparrow F by WAYBEL_0:def 16;
          then a "/\" b in W by A27,A32,XBOOLE_0:def 4;
          hence inf {a,b} in the carrier of SW by A29,YELLOW_0:40;
        end;
      end;
    end;

    assume
A34:   N is with_open_semilattices;
    let x be Point of S;
    reconsider y = x as Point of N by A1;
    consider J being Basis of y such that
A35:  for A being Subset of N st A in J holds subrelstr A is meet-inheriting
      by A34,Def4;
    reconsider J' = {uparrow A where A is Subset of N: A in J}
     as Basis of x by Th16;
    take J';
    let W be Subset of S;
    assume W in J';
    then consider V being Subset of N such that
A36:   W = uparrow V and
A37:   V in J;
A38: x in V by A37,YELLOW_8:21;
A39: V c= uparrow V by WAYBEL_0:16;
      subrelstr V is meet-inheriting by A35,A37;
    then V is filtered by YELLOW12:26;
    then uparrow V is filtered by WAYBEL_0:35;
    hence W is Filter of S by A1,A36,A38,A39,WAYBEL_0:4,25;
  end;

:: Theorem 2.12, p. 155,  r => l
theorem Th33:
 for N being Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N
   for x being Element of N holds
  {inf A where A is Subset of S : x in A & A in sigma S} c=
   {inf J where J is Subset of N : x in J & J in lambda N}
  proof
    let N be Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        x be Element of N;
A1: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    set s = {inf A where A is Subset of S : x in A & A in sigma S},
        l = {inf J where J is Subset of N : x in J & J in lambda N};
    let k be set;
    assume k in s;
    then consider J being Subset of S such that
A2:   k = inf J & x in J & J in sigma S;
    reconsider A = J as Subset of N by A1;
      ex_inf_of A,N by YELLOW_0:17;
then A3: inf A = inf J by A1,YELLOW_0:27;
      sigma N c= lambda N by Th10;
    then sigma S c= lambda N by A1,YELLOW_9:52;
    hence k in l by A2,A3;
  end;

:: Theorem 2.12, p. 155
theorem Th34:
 for N being meet-continuous Lawson (complete TopLattice)
  for S being Scott TopAugmentation of N
   for x being Element of N holds
  {inf A where A is Subset of S : x in A & A in sigma S} =
  {inf J where J is Subset of N : x in J & J in lambda N}
  proof
    let N be meet-continuous Lawson (complete TopLattice),
        S be Scott TopAugmentation of N,
        x be Element of N;
A1: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
    set l = {inf A where A is Subset of N : x in A & A in lambda N},
        s = {inf J where J is Subset of S : x in J & J in sigma S};
    thus s c= l by Th33;
    let k be set;
    assume k in l;
    then consider A being Subset of N such that
A2:   k = inf A & x in A & A in lambda N;
    reconsider J = A as Subset of S by A1;
A3: ex_inf_of J,S by YELLOW_0:17;
then A4: inf A = inf J by A1,YELLOW_0:27
         .= inf uparrow J by A3,WAYBEL_0:38;
A5: J c= uparrow J by WAYBEL_0:16;
      A is open by A2,Th12;
    then uparrow J is open by Th15;
    then uparrow J in sigma S by WAYBEL14:24;
    hence k in s by A2,A4,A5;
  end;

:: Theorem 2.13, p. 155,  1 <=> 2
theorem Th35:
 for N being meet-continuous Lawson (complete TopLattice) holds
  N is continuous iff
   N is with_open_semilattices & InclPoset sigma N is continuous
  proof
    let N be meet-continuous Lawson (complete TopLattice);
    consider S being Scott TopAugmentation of N;
A1: the RelStr of N = the RelStr of S by YELLOW_9:def 4;
then A2: sigma S = sigma N by YELLOW_9:52;
    hereby
      assume N is continuous;
then A3:   S is continuous by A1,YELLOW12:15;
        for x being Point of S ex J being Basis of x st
       for W being Subset of S st W in J holds W is Filter of S
      proof
        let x be Point of S;
        consider J being Basis of x such that
A4:       for W being Subset of S st W in J holds W is open filtered
           by A3,WAYBEL14:35;
        take J;
        let W be Subset of S; assume
A5:       W in J;
        then W is open by A4;
        hence W is Filter of S by A4,A5,WAYBEL11:def 4,YELLOW_8:21;
      end;
      hence N is with_open_semilattices by Th32;
        InclPoset sigma S is continuous by A3,WAYBEL14:36;
      hence InclPoset sigma N is continuous by A1,YELLOW_9:52;
    end;
    assume
A6:   N is with_open_semilattices & InclPoset sigma N is continuous;
      for x being Element of S ex J being Basis of x st
     for Y being Subset of S st Y in J holds Y is open filtered
    proof
      let x be Element of S;
      reconsider y = x as Element of N by A1;
      consider J being Basis of y such that
A7:     for A being Subset of N st A in J holds subrelstr A is meet-inheriting
          by A6,Def4;
      reconsider J' = {uparrow A where A is Subset of N: A in J} as Basis of x
       by Th16;
      take J';
      let Y be Subset of S; assume
A8:     Y in J';
      then consider A being Subset of N such that
A9:     Y = uparrow A and
A10:     A in J;
        subrelstr A is meet-inheriting by A7,A10;
      then A is filtered by YELLOW12:26;
      then uparrow A is filtered by WAYBEL_0:35;
      hence Y is open filtered by A1,A8,A9,WAYBEL_0:4,YELLOW_8:21;
    end;
    then for x being Element of S holds x = "\/" ({inf X where X is Subset of
S :
     x in X & X in sigma S}, S) by A2,A6,WAYBEL14:37;
    then S is continuous by WAYBEL14:38;
    hence N is continuous by A1,YELLOW12:15;
  end;

definition
 cluster continuous -> with_open_semilattices (Lawson complete TopLattice);
coherence
  proof
    let N be Lawson complete TopLattice;
    assume N is continuous;
    then reconsider M = N as continuous Lawson complete TopLattice;
      M is with_open_semilattices by Th35;
    hence thesis;
  end;
end;

definition let N be continuous Lawson (complete TopLattice);
 cluster InclPoset sigma N -> continuous;
coherence by Th35;
end;

:: Theorem 2.13, p. 155,  1 => 3
theorem
   for N being continuous Lawson (complete TopLattice) holds
  N is compact Hausdorff topological_semilattice with_open_semilattices
  proof
    let N be continuous Lawson (complete TopLattice);
    thus N is compact Hausdorff;
      InclPoset sigma N is continuous;
    hence N is topological_semilattice by Th22;
    thus N is with_open_semilattices;
  end;

:: Theorem 2.13, p. 155,  3 => 3'
theorem
   for N being Hausdorff topological_semilattice with_open_semilattices
  Lawson (complete TopLattice) holds
   N is with_compact_semilattices
  proof
    let N be Hausdorff topological_semilattice with_open_semilattices
        Lawson (complete TopLattice);
    let x be Point of N;
    consider BO being Basis of x such that
A1:   for A being Subset of N st A in BO holds subrelstr A is meet-inheriting
        by Def4;
    set BC = {Cl A where A is Subset of N: A in BO};
      BC is Subset-Family of N
    proof
        BC c= bool the carrier of N
      proof
        let k be set;
        assume k in BC;
        then consider A being Subset of N such that
A2:       k = Cl A and A in BO;
        thus k in bool the carrier of N by A2;
      end;
      hence thesis by SETFAM_1:def 7;
    end;
    then reconsider BC as Subset-Family of N;
      BC is basis of x
    proof
      let S be a_neighborhood of x;
     x in Int S by CONNSP_2:def 1;
      then consider W being Subset of N such that
A3:     W in BO and
A4:     W c= Int S by YELLOW_8:22;
A5:   x in W & W is open by A3,YELLOW_8:21;
      then x in Int W by TOPS_1:55;
      then reconsider T = W as a_neighborhood of x by CONNSP_2:def 1;
A6:   Int S c= S by TOPS_1:44;
      per cases;
      suppose
A7:    W <> [#]N;
        x in W by A3,YELLOW_8:21;
  then {x} c= W by ZFMISC_1:37;
      then consider G being Subset of N such that
A8:    G is open and
A9:    {x} c= G and
A10:    Cl G c= W by A5,A7,CONNSP_2:26;
        x in G by A9,ZFMISC_1:37;
      then consider K being Subset of N such that
A11:    K in BO and
A12:    K c= G by A8,YELLOW_8:22;
        x in K & K is open by A11,YELLOW_8:21;
then A13:   x in Int K by TOPS_1:55;
        K c= Cl K by PRE_TOPC:48;
      then Int K c= Int Cl K by TOPS_1:48;
      then reconsider KK = Cl K as a_neighborhood of x by A13,CONNSP_2:def 1;
      take KK;
      thus KK in BC by A11;
        Cl K c= Cl G by A12,PRE_TOPC:49;
      then Cl K c= W by A10,XBOOLE_1:1;
      then KK c= Int S by A4,XBOOLE_1:1;
      hence KK c= S by A6,XBOOLE_1:1;
      suppose
A14:    W = [#]N;
      take T;
        Cl [#]N = [#]N by TOPS_1:27;
      hence T in BC by A3,A14;
      thus T c= S by A4,A6,XBOOLE_1:1;
    end;
    then reconsider BC as basis of x;
    take BC;
    let A be Subset of N;
    assume A in BC;
    then consider C being Subset of N such that
A15:  A = Cl C and
A16:  C in BO;
      subrelstr C is meet-inheriting by A1,A16;
    hence subrelstr A is meet-inheriting by A15,Th31;
    thus A is compact by A15,COMPTS_1:17;
  end;

:: Theorem 2.13, p. 155,  3' => 4
theorem
   for N being meet-continuous Hausdorff Lawson (complete TopLattice),
     x being Element of N holds
   x = "\/"({inf V where V is Subset of N: x in V & V in lambda N},N)
  proof
    let N be meet-continuous Hausdorff Lawson (complete TopLattice),
        x be Element of N;
    consider S being Scott complete TopAugmentation of N;
A1: the RelStr of S = the RelStr of N by YELLOW_9:def 4;
    then reconsider y = x as Element of S;
A2: for y being Element of S ex J being Basis of y st
     for X being Subset of S st X in J holds X is open filtered by WAYBEL14:35;
A3: ex_sup_of {inf X where X is Subset of S: y in X & X in sigma S}, S
      by YELLOW_0:17;
      InclPoset sigma S is continuous by WAYBEL14:36;
    hence
      x = "\/" ({inf X where X is Subset of S: y in X & X in sigma S}, S)
         by A2,WAYBEL14:37
     .= "\/" ({inf X where X is Subset of S: x in X & X in sigma S}, N)
         by A1,A3,YELLOW_0:26
     .= "\/" ({inf V where V is Subset of N: x in V & V in lambda N}, N)
         by Th34;
  end;

:: Theorem 2.13, p. 155,  1 <=> 4
theorem
   for N being meet-continuous Lawson (complete TopLattice) holds
  N is continuous iff
   for x being Element of N holds
    x = "\/"({inf V where V is Subset of N: x in V & V in lambda N},N)
  proof
    let N be meet-continuous Lawson (complete TopLattice);
    consider S being complete Scott TopAugmentation of N;
A1: the RelStr of S = the RelStr of N by YELLOW_9:def 4;
    hereby assume
A2:     N is continuous;
      let x be Element of N;
A3:   x is Element of S by A1;
A4:   S is continuous by A1,A2,YELLOW12:15;
then A5:   InclPoset sigma S is continuous by WAYBEL14:36;
A6:   ex_sup_of {inf X where X is Subset of S: x in X & X in sigma S}, N
        by YELLOW_0:17;
        for x being Element of S ex J being Basis of x st
       for Y being Subset of S st Y in J holds Y is open filtered
         by A4,WAYBEL14:35;
      hence x = "\/" ({inf X where X is Subset of S: x in X & X in sigma S}, S
)
             by A3,A5,WAYBEL14:37
        .= "\/" ({inf X where X is Subset of S: x in X & X in sigma S}, N)
             by A1,A6,YELLOW_0:26
        .= "\/"({inf V where V is Subset of N: x in V & V in lambda N},N)
             by Th34;
    end;
    assume
A7:  for x being Element of N holds
      x = "\/"({inf V where V is Subset of N: x in V & V in lambda N},N);
      now
      let x be Element of S;
A8:   x is Element of N by A1;
A9:   ex_sup_of {inf X where X is Subset of S: x in X & X in sigma S}, N
        by YELLOW_0:17;
      thus x = "\/"({inf V where V is Subset of N: x in V & V in lambda N},N)
         by A7,A8
       .= "\/"({inf V where V is Subset of S: x in V & V in sigma S},N)
         by A8,Th34
       .= "\/"({inf V where V is Subset of S: x in V & V in sigma S},S)
         by A1,A9,YELLOW_0:26;
    end;
    then S is continuous by WAYBEL14:38;
    hence thesis by A1,YELLOW12:15;
  end;

:: Exercise 2.16, p. 156,  1 <=> 2
theorem Th40:
 for N being meet-continuous Lawson (complete TopLattice) holds
  N is algebraic iff
  N is with_open_semilattices & InclPoset sigma N is algebraic
  proof
    let N be meet-continuous Lawson (complete TopLattice);
    consider S being Scott TopAugmentation of N;
A1: the RelStr of S = the RelStr of N by YELLOW_9:def 4;
    hereby
      assume
A2:     N is algebraic;
      then reconsider M = N as algebraic LATTICE;
        M is continuous;
      hence N is with_open_semilattices by Th35;
        S is algebraic by A1,A2,WAYBEL_8:17;
      then ex K being Basis of S st K = {uparrow x where x is Element of S:
        x in the carrier of CompactSublatt S} by WAYBEL14:42;
      then InclPoset sigma S is algebraic by WAYBEL14:43;
      hence InclPoset sigma N is algebraic by A1,YELLOW_9:52;
    end;
    assume that
A3:   N is with_open_semilattices and
A4:   InclPoset sigma N is algebraic;
    reconsider T = InclPoset sigma N as algebraic LATTICE by A4;
      T is continuous;
    then N is continuous by A3,Th35;
    then S is continuous by A1,YELLOW12:15;
    then for x being Element of S ex K being Basis of x st for Y being Subset
of S
     st Y in K holds Y is open filtered by WAYBEL14:35;
then A5: for V being Element of InclPoset sigma S
     ex VV being Subset of InclPoset sigma S st V = sup VV &
      for W being Element of InclPoset sigma S st W in VV holds W is co-prime
       by WAYBEL14:39;
      InclPoset sigma S is algebraic by A1,A4,YELLOW_9:52;
    then ex K being Basis of S st K = {uparrow x where x is Element of S:
     x in the carrier of CompactSublatt S} by A5,WAYBEL14:44;
    then S is algebraic by WAYBEL14:45;
    hence thesis by A1,WAYBEL_8:17;
  end;

definition let N be meet-continuous algebraic Lawson (complete TopLattice);
 cluster InclPoset sigma N -> algebraic;
coherence by Th40;
end;

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