let I be BinOp of [.0,1.]; for N being Fuzzy_Negation st I is satisfying_(I1) & I is N -satisfying_CP holds
I is satisfying_(I2)
let N be Fuzzy_Negation; ( I is satisfying_(I1) & I is N -satisfying_CP implies I is satisfying_(I2) )
assume that
A0:
I is satisfying_(I1)
and
AA:
I is N -satisfying_CP
; I is satisfying_(I2)
for x, y, z being Element of [.0,1.] st y <= z holds
I . (x,y) <= I . (x,z)
proof
let x,
y,
z be
Element of
[.0,1.];
( y <= z implies I . (x,y) <= I . (x,z) )
assume
y <= z
;
I . (x,y) <= I . (x,z)
then
N . z <= N . y
by FUZIMPL3:7;
then A1:
I . (
(N . y),
(N . x))
<= I . (
(N . z),
(N . x))
by A0;
I . (
x,
y)
= I . (
(N . y),
(N . x))
by AA;
hence
I . (
x,
y)
<= I . (
x,
z)
by A1, AA;
verum
end;
hence
I is satisfying_(I2)
; verum