let D be non empty set ; for RD being Equivalence_Relation of D
for F, G being BinOp of D,RD st F absorbs G holds
F /\/ RD absorbs G /\/ RD
let RD be Equivalence_Relation of D; for F, G being BinOp of D,RD st F absorbs G holds
F /\/ RD absorbs G /\/ RD
let F, G be BinOp of D,RD; ( F absorbs G implies F /\/ RD absorbs G /\/ RD )
deffunc H3( Element of D) -> Element of Class RD = EqClass RD,$1;
defpred S1[ Element of Class RD, Element of Class RD] means (F /\/ RD) . $1,((G /\/ RD) . $1,$2) = $1;
assume A1:
for x, y being Element of D holds F . x,(G . x,y) = x
; LATTICE2:def 1 F /\/ RD absorbs G /\/ RD
A2:
now let x1,
x2 be
Element of
D;
S1[ EqClass RD,x1, EqClass RD,x2](F /\/ RD) . H3(
x1),
((G /\/ RD) . H3(x1),H3(x2)) =
(F /\/ RD) . H3(
x1),
H3(
G . x1,
x2)
by Th3
.=
H3(
F . x1,
(G . x1,x2))
by Th3
.=
H3(
x1)
by A1
;
hence
S1[
EqClass RD,
x1,
EqClass RD,
x2]
;
verum end;
thus
for x, y being Element of Class RD holds S1[x,y]
from FILTER_1:sch 2(A2); LATTICE2:def 1 verum