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 for x1, x2 being Element of D holds S1[ EqClass (RD,x1), EqClass (RD,x2)]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