let X, Y be set ; :: thesis: for C being non empty set
for f1, f2 being PartFunc of C,COMPLEX st f1 | X is bounded & f2 | Y is constant holds
( (f1 - f2) | (X /\ Y) is bounded & (f2 - f1) | (X /\ Y) is bounded & (f1 (#) f2) | (X /\ Y) is bounded )
let C be non empty set ; :: thesis: for f1, f2 being PartFunc of C,COMPLEX st f1 | X is bounded & f2 | Y is constant holds
( (f1 - f2) | (X /\ Y) is bounded & (f2 - f1) | (X /\ Y) is bounded & (f1 (#) f2) | (X /\ Y) is bounded )
let f1, f2 be PartFunc of C,COMPLEX ; :: thesis: ( f1 | X is bounded & f2 | Y is constant implies ( (f1 - f2) | (X /\ Y) is bounded & (f2 - f1) | (X /\ Y) is bounded & (f1 (#) f2) | (X /\ Y) is bounded ) )
assume A1:
( f1 | X is bounded & f2 | Y is constant )
; :: thesis: ( (f1 - f2) | (X /\ Y) is bounded & (f2 - f1) | (X /\ Y) is bounded & (f1 (#) f2) | (X /\ Y) is bounded )
then
(- f2) | Y is constant
by Th92;
hence
(f1 - f2) | (X /\ Y) is bounded
by A1, Th95; :: thesis: ( (f2 - f1) | (X /\ Y) is bounded & (f1 (#) f2) | (X /\ Y) is bounded )
A2:
f2 | Y is bounded
by A1, Th93;
hence
(f2 - f1) | (X /\ Y) is bounded
by A1, Th88; :: thesis: (f1 (#) f2) | (X /\ Y) is bounded
thus
(f1 (#) f2) | (X /\ Y) is bounded
by A1, A2, Th88; :: thesis: verum