let L be complete noetherian Lattice; JIRRS L is supremum-dense
defpred S1[ Element of (LattPOSet L)] means ex D9 being Subset of (JIRRS L) st % $1 = "\/" (D9,L);
A1:
for x being Element of (LattPOSet L) st ( for y being Element of (LattPOSet L) st y <> x & [y,x] in the InternalRel of (LattPOSet L) holds
S1[y] ) holds
S1[x]
proof
let x be
Element of
(LattPOSet L);
( ( for y being Element of (LattPOSet L) st y <> x & [y,x] in the InternalRel of (LattPOSet L) holds
S1[y] ) implies S1[x] )
set X =
{ d where d is Element of L : ( d [= % x & d <> % x ) } ;
A2:
for
u being
Element of
L st
u in { d where d is Element of L : ( d [= % x & d <> % x ) } holds
(
u % <> x &
[(u %),x] in the
InternalRel of
(LattPOSet L) )
assume A5:
for
y being
Element of
(LattPOSet L) st
y <> x &
[y,x] in the
InternalRel of
(LattPOSet L) holds
S1[
y]
;
S1[x]
A6:
for
u being
Element of
L st
u in { d where d is Element of L : ( d [= % x & d <> % x ) } holds
S1[
u % ]
per cases
( % x is completely-join-irreducible or not % x is completely-join-irreducible )
;
suppose A8:
not
% x is
completely-join-irreducible
;
S1[x]set G =
{ H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } ;
set D9 =
union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } ;
A9:
*' (% x) = % x
by A8;
A10:
for
r being
Element of
L st
union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } is_less_than r holds
% x [= r
for
v being
object st
v in union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } holds
v in JIRRS L
then A18:
union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } is
Subset of
(JIRRS L)
by TARSKI:def 3;
for
q being
Element of
L st
q in union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } holds
q [= % x
proof
let q be
Element of
L;
( q in union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } implies q [= % x )
assume
q in union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) }
;
q [= % x
then consider h being
set such that A19:
q in h
and A20:
h in { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) }
by TARSKI:def 4;
ex
h9 being
Subset of
(JIRRS L) st
(
h9 = h & ex
u being
Element of
(LattPOSet L) st
(
% u in { d where d is Element of L : ( d [= % x & d <> % x ) } &
% u = "\/" (
h9,
L) ) )
by A20;
then consider u being
Element of
(LattPOSet L) such that A21:
% u in { d where d is Element of L : ( d [= % x & d <> % x ) }
and A22:
% u = "\/" (
h,
L)
;
h is_less_than % u
by A22, LATTICE3:def 21;
then A23:
q [= % u
by A19, LATTICE3:def 17;
{ d where d is Element of L : ( d [= % x & d <> % x ) } is_less_than % x
by A9, LATTICE3:def 21;
then
% u [= % x
by A21, LATTICE3:def 17;
hence
q [= % x
by A23, LATTICES:7;
verum
end; then
union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } is_less_than % x
by LATTICE3:def 17;
then
% x = "\/" (
(union { H where H is Subset of (JIRRS L) : ex u being Element of (LattPOSet L) st
( % u in { d where d is Element of L : ( d [= % x & d <> % x ) } & % u = "\/" (H,L) ) } ),
L)
by A10, LATTICE3:def 21;
hence
S1[
x]
by A18;
verum end; end;
end;
A24:
LattPOSet L is well_founded
by Def3;
A25:
for x being Element of (LattPOSet L) holds S1[x]
from WELLFND1:sch 3(A1, A24);
for a being Element of L ex D9 being Subset of (JIRRS L) st a = "\/" (D9,L)
hence
JIRRS L is supremum-dense
; verum