let X be set ; for S being RealNormSpace
for f, g being PartFunc of S,RNS_Real st f is_continuous_on X & g = ||.f.|| holds
g is_continuous_on X
let S be RealNormSpace; for f, g being PartFunc of S,RNS_Real st f is_continuous_on X & g = ||.f.|| holds
g is_continuous_on X
let f, g be PartFunc of S,RNS_Real; ( f is_continuous_on X & g = ||.f.|| implies g is_continuous_on X )
assume that
A1:
f is_continuous_on X
and
A2:
g = ||.f.||
; g is_continuous_on X
||.(f | X).|| = g | X
by A2, NFCONT_1:35;
hence
g is_continuous_on X
by A1, A2, Th21, NORMSP_0:def 2; verum