set N = N_CC ;
set I = I_LK ;
for x, y being Element of [.0,1.] holds I_LK . (x,(N_CC . y)) = I_LK . (y,(N_CC . x))
proof
let x,
y be
Element of
[.0,1.];
I_LK . (x,(N_CC . y)) = I_LK . (y,(N_CC . x))
I_LK . (
x,
(N_CC . y)) =
min (1,
((1 - x) + (N_CC . y)))
by FUZIMPL1:def 14
.=
min (1,
((1 - x) + (1 - y)))
by FUZIMPL3:def 6
.=
min (1,
((1 - y) + (N_CC . x)))
by FUZIMPL3:def 6
.=
I_LK . (
y,
(N_CC . x))
by FUZIMPL1:def 14
;
hence
I_LK . (
x,
(N_CC . y))
= I_LK . (
y,
(N_CC . x))
;
verum
end;
hence
I_LK is N_CC -satisfying_R-CP
; verum