set f = Kleene-Dienes_implication ;
a0:
for x1, x2, y being Element of [.0,1.] st x1 <= x2 holds
Kleene-Dienes_implication . (x1,y) >= Kleene-Dienes_implication . (x2,y)
proof
let x1,
x2,
y be
Element of
[.0,1.];
( x1 <= x2 implies Kleene-Dienes_implication . (x1,y) >= Kleene-Dienes_implication . (x2,y) )
assume
x1 <= x2
;
Kleene-Dienes_implication . (x1,y) >= Kleene-Dienes_implication . (x2,y)
then
- x2 <= - x1
by XREAL_1:24;
then
1
+ (- x2) <= 1
+ (- x1)
by XREAL_1:7;
then
max (
(1 - x2),
y)
<= max (
(1 - x1),
y)
by XXREAL_0:26;
then
Kleene-Dienes_implication . (
x2,
y)
<= max (
(1 - x1),
y)
by Kleene;
hence
Kleene-Dienes_implication . (
x1,
y)
>= Kleene-Dienes_implication . (
x2,
y)
by Kleene;
verum
end;
aa:
for x, y1, y2 being Element of [.0,1.] st y1 <= y2 holds
Kleene-Dienes_implication . (x,y1) <= Kleene-Dienes_implication . (x,y2)
proof
let x,
y1,
y2 be
Element of
[.0,1.];
( y1 <= y2 implies Kleene-Dienes_implication . (x,y1) <= Kleene-Dienes_implication . (x,y2) )
assume
y1 <= y2
;
Kleene-Dienes_implication . (x,y1) <= Kleene-Dienes_implication . (x,y2)
then
max (
(1 - x),
y1)
<= max (
(1 - x),
y2)
by XXREAL_0:26;
then
max (
(1 - x),
y1)
<= Kleene-Dienes_implication . (
x,
y2)
by Kleene;
hence
Kleene-Dienes_implication . (
x,
y1)
<= Kleene-Dienes_implication . (
x,
y2)
by Kleene;
verum
end;
AA:
( 0 in [.0,1.] & 1 in [.0,1.] )
by XXREAL_1:1;
then A1: Kleene-Dienes_implication . (0,0) =
max ((1 - 0),0)
by Kleene
.=
1
by XXREAL_0:def 10
;
A2: Kleene-Dienes_implication . (1,1) =
max ((1 - 1),1)
by AA, Kleene
.=
1
by XXREAL_0:def 10
;
Kleene-Dienes_implication . (1,0) =
max ((1 - 1),0)
by AA, Kleene
.=
0
;
hence
( Kleene-Dienes_implication is decreasing_on_1st & Kleene-Dienes_implication is increasing_on_2nd & Kleene-Dienes_implication is 00-dominant & Kleene-Dienes_implication is 11-dominant & Kleene-Dienes_implication is 10-weak )
by A1, A2, a0, aa; verum