:: More on the Lattice of Congruences in a Many Sorted Algebra
:: by Robert Milewski
::
:: Received March 6, 1996
:: Copyright (c) 1996-2021 Association of Mizar Users
:: (Stowarzyszenie Uzytkownikow Mizara, Bialystok, Poland).
:: This code can be distributed under the GNU General Public Licence
:: version 3.0 or later, or the Creative Commons Attribution-ShareAlike
:: License version 3.0 or later, subject to the binding interpretation
:: detailed in file COPYING.interpretation.
:: See COPYING.GPL and COPYING.CC-BY-SA for the full text of these
:: licenses, or see http://www.gnu.org/licenses/gpl.html and
:: http://creativecommons.org/licenses/by-sa/3.0/.
environ
vocabularies XBOOLE_0, PBOOLE, SUBSET_1, NUMBERS, FINSEQ_1, STRUCT_0,
MSUALG_1, RELAT_1, XXREAL_0, ARYTM_3, FUNCT_1, MSUALG_5, EQREL_1, TARSKI,
LATTICES, XXREAL_2, REWRITE1, LATTICE3, SETFAM_1, ZFMISC_1, CARD_1,
MSUALG_4, CLOSURE2, NAT_1, MARGREL1, PARTFUN1, FUNCT_4, FINSET_1, CARD_3,
MSUALG_6, MSUALG_7, MSUALG_8;
notations TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, SETFAM_1, RELAT_1, RELSET_1,
DOMAIN_1, ORDINAL1, NUMBERS, XCMPLX_0, STRUCT_0, NAT_1, BINOP_1, FUNCT_1,
PARTFUN1, FUNCT_2, FINSET_1, FINSEQ_1, CARD_3, REWRITE1, EQREL_1,
LATTICES, LATTICE3, PBOOLE, MSSUBFAM, MSUALG_1, MSUALG_4, MSUALG_5,
CLOSURE2, MSUALG_6, MSUALG_7, XXREAL_0;
constructors BINOP_1, NAT_1, MEMBERED, REALSET1, REWRITE1, MSSUBFAM, LATTICE3,
MSUALG_5, CLOSURE2, MSUALG_6, MSUALG_7, RELSET_1, NUMBERS;
registrations SUBSET_1, RELSET_1, PARTFUN1, FINSET_1, MEMBERED, EQREL_1,
PBOOLE, STRUCT_0, LATTICES, MSUALG_1, MSUALG_3, MSUALG_5, CLOSURE2,
MSUALG_6, MSUALG_7, FUNCT_1, XXREAL_0;
requirements NUMERALS, SUBSET, BOOLE, ARITHM;
begin
:: MORE ON THE LATTICE OF EQUIVALENCE RELATIONS ::
reserve I for non empty set;
reserve M for ManySortedSet of I;
reserve Y,x,y,y1,i,j for set;
reserve k for Element of NAT;
reserve p for FinSequence;
reserve S for non void non empty ManySortedSign;
reserve A for non-empty MSAlgebra over S;
theorem :: MSUALG_8:1
for n be Nat, p be FinSequence holds 1 <= n & n <
len p iff n in dom p & n+1 in dom p;
scheme :: MSUALG_8:sch 1
NonUniqSeqEx{A()->(Element of NAT),P[object,object]}:
ex p st dom p = Seg A() & for k st k in Seg A() holds P[k,p.k]
provided
for k st k in Seg A() ex x being object st P[k,x];
theorem :: MSUALG_8:2
for a,b be Element of EqRelLatt Y for A,B be Equivalence_Relation
of Y st a = A & b = B holds a [= b iff A c= B;
registration
let Y;
cluster EqRelLatt Y -> bounded;
end;
theorem :: MSUALG_8:3
Bottom EqRelLatt Y = id Y;
theorem :: MSUALG_8:4
Top EqRelLatt Y = nabla Y;
theorem :: MSUALG_8:5
EqRelLatt Y is complete;
registration
let Y;
cluster EqRelLatt Y -> complete;
end;
theorem :: MSUALG_8:6
for Y be set for X be Subset of EqRelLatt Y holds union X is Relation of Y;
theorem :: MSUALG_8:7
for Y be set for X be Subset of EqRelLatt Y holds union X c= "\/" X;
theorem :: MSUALG_8:8
for Y be set for X be Subset of EqRelLatt Y for R be Relation of
Y st R = union X holds "\/" X = EqCl R;
theorem :: MSUALG_8:9
for Y be set for X be Subset of EqRelLatt Y for R be Relation st
R = union X holds R = R~;
theorem :: MSUALG_8:10
for Y be set for X be Subset of EqRelLatt Y holds x in Y & y in
Y implies ( [x,y] in "\/" X iff ex f being FinSequence st 1 <= len f & x = f.1
& y = f.(len f) & for i be Nat st 1 <= i & i < len f holds [f.i,f.(i
+1)] in union X );
begin :: Lattice of Congruences in a Many Sorted Algebra as a Sublattice
:: of Lattice of Many Sorted Equivalence Relations Inheriting Sups and Infs
theorem :: MSUALG_8:11
for B be Subset of CongrLatt A holds "/\" (B,EqRelLatt the Sorts
of A) is MSCongruence of A;
definition
let S,A;
let E be Element of EqRelLatt the Sorts of A;
func CongrCl E -> MSCongruence of A equals
:: MSUALG_8:def 1
"/\" ({x where x is Element of
EqRelLatt the Sorts of A : x is MSCongruence of A & E [= x},EqRelLatt the Sorts
of A);
end;
definition
let S,A;
let X be Subset of EqRelLatt the Sorts of A;
func CongrCl X -> MSCongruence of A equals
:: MSUALG_8:def 2
"/\" ({x where x is Element of
EqRelLatt the Sorts of A : x is MSCongruence of A & X is_less_than x},EqRelLatt
the Sorts of A);
end;
theorem :: MSUALG_8:12
for C be Element of EqRelLatt the Sorts of A st C is MSCongruence of A
holds CongrCl C = C;
theorem :: MSUALG_8:13
for X be Subset of EqRelLatt the Sorts of A holds CongrCl "\/" (X,
EqRelLatt the Sorts of A) = CongrCl X;
theorem :: MSUALG_8:14
for B1,B2 be Subset of CongrLatt A, C1,C2 be MSCongruence of A st C1 =
"\/"(B1,EqRelLatt the Sorts of A) & C2 = "\/"(B2,EqRelLatt the Sorts of A)
holds C1 "\/" C2 = "\/"(B1 \/ B2,EqRelLatt the Sorts of A);
theorem :: MSUALG_8:15
for X be Subset of CongrLatt A holds "\/" (X,EqRelLatt the Sorts of A)
= "\/" ({ "\/" (X0,EqRelLatt the Sorts of A) where X0 is Subset of EqRelLatt
the Sorts of A : X0 is finite Subset of X },EqRelLatt the Sorts of A);
theorem :: MSUALG_8:16
for i be Element of I for e be Equivalence_Relation of M.i ex E
be Equivalence_Relation of M st E.i = e & for j be Element of I st j <> i holds
E.j = nabla (M.j);
notation
let I be non empty set;
let M be ManySortedSet of I;
let i be Element of I;
let X be Subset of EqRelLatt M;
synonym EqRelSet (X,i) for pi(X,i);
end;
definition
let I be non empty set;
let M be ManySortedSet of I;
let i be Element of I;
let X be Subset of EqRelLatt M;
redefine func EqRelSet (X,i) -> Subset of EqRelLatt M.i means
:: MSUALG_8:def 3
x in it iff ex Eq be Equivalence_Relation of M st x = Eq.i & Eq in X;
end;
theorem :: MSUALG_8:17
for i be Element of S for X be Subset of EqRelLatt the Sorts of
A for B be Equivalence_Relation of the Sorts of A st B = "\/" X holds B.i =
"\/" (EqRelSet (X,i) , EqRelLatt (the Sorts of A).i);
theorem :: MSUALG_8:18
for X be Subset of CongrLatt A holds "\/" (X,EqRelLatt the Sorts
of A) is MSCongruence of A;
theorem :: MSUALG_8:19
CongrLatt A is /\-inheriting;
theorem :: MSUALG_8:20
CongrLatt A is \/-inheriting;
registration
let S,A;
cluster CongrLatt A -> /\-inheriting \/-inheriting;
end;