set X = [.0,1.];
let f be bijective increasing UnOp of [.0,1.]; f " is increasing
A2:
((f | [.0,1.]) ") | (f .: [.0,1.]) is increasing
by FC9;
A3:
( dom f = [.0,1.] & rng f = [.0,1.] )
by FUNCT_2:def 1, FUNCT_2:def 3;
f .: [.0,1.] = [.0,1.]
by RELAT_1:113, A3;
hence
f " is increasing
by A2; verum