let g be Complex; for X being set
for f being PartFunc of COMPLEX,COMPLEX st f is_continuous_on X holds
g (#) f is_continuous_on X
let X be set ; for f being PartFunc of COMPLEX,COMPLEX st f is_continuous_on X holds
g (#) f is_continuous_on X
let f be PartFunc of COMPLEX,COMPLEX; ( f is_continuous_on X implies g (#) f is_continuous_on X )
assume A1:
f is_continuous_on X
; g (#) f is_continuous_on X
then A2:
X c= dom f
;
then A3:
X c= dom (g (#) f)
by CFUNCT_1:4;
now for s1 being Complex_Sequence st rng s1 c= X & s1 is convergent & lim s1 in X holds
( (g (#) f) /* s1 is convergent & (g (#) f) /. (lim s1) = lim ((g (#) f) /* s1) )let s1 be
Complex_Sequence;
( rng s1 c= X & s1 is convergent & lim s1 in X implies ( (g (#) f) /* s1 is convergent & (g (#) f) /. (lim s1) = lim ((g (#) f) /* s1) ) )assume that A4:
rng s1 c= X
and A5:
s1 is
convergent
and A6:
lim s1 in X
;
( (g (#) f) /* s1 is convergent & (g (#) f) /. (lim s1) = lim ((g (#) f) /* s1) )A7:
f /* s1 is
convergent
by A1, A4, A5, A6, Th38;
then A8:
g (#) (f /* s1) is
convergent
;
A9:
lim s1 in dom (g (#) f)
by A3, A6;
f /. (lim s1) = lim (f /* s1)
by A1, A4, A5, A6, Th38;
then (g (#) f) /. (lim s1) =
g * (lim (f /* s1))
by CFUNCT_1:4, A9
.=
lim (g (#) (f /* s1))
by A7, COMSEQ_2:18
.=
lim ((g (#) f) /* s1)
by A2, A4, Th8, XBOOLE_1:1
;
hence
(
(g (#) f) /* s1 is
convergent &
(g (#) f) /. (lim s1) = lim ((g (#) f) /* s1) )
by A2, A4, A8, Th8, XBOOLE_1:1;
verum end;
hence
g (#) f is_continuous_on X
by A3, Th38; verum