let fi be Fuzzy_Implication; for x being Element of [.0,1.] holds fi . (x,1) = 1
let x be Element of [.0,1.]; fi . (x,1) = 1
A1:
fi . (1,1) = 1
by Def11;
B1:
1 in [.0,1.]
by XXREAL_1:1;
reconsider z = 1 as Element of [.0,1.] by XXREAL_1:1;
x <= 1
by XXREAL_1:1;
then B2:
fi . (1,1) <= fi . (x,1)
by DefDecr, B1;
fi . (x,z) in [.0,1.]
;
then
fi . (x,1) <= 1
by XXREAL_1:1;
hence
fi . (x,1) = 1
by XXREAL_0:1, A1, B2; verum