let X be set ; for r being Real
for S being RealNormSpace
for f being PartFunc of REAL, the carrier of S st X c= dom f & f | X is continuous holds
(r (#) f) | X is continuous
let r be Real; for S being RealNormSpace
for f being PartFunc of REAL, the carrier of S st X c= dom f & f | X is continuous holds
(r (#) f) | X is continuous
let S be RealNormSpace; for f being PartFunc of REAL, the carrier of S st X c= dom f & f | X is continuous holds
(r (#) f) | X is continuous
let f be PartFunc of REAL, the carrier of S; ( X c= dom f & f | X is continuous implies (r (#) f) | X is continuous )
assume that
A1:
X c= dom f
and
A2:
f | X is continuous
; (r (#) f) | X is continuous
A3:
X c= dom (r (#) f)
by A1, VFUNCT_1:def 4;
now let s1 be
Real_Sequence;
( rng s1 c= X & s1 is convergent & lim s1 in X implies ( (r (#) f) /* s1 is convergent & (r (#) f) /. (lim s1) = lim ((r (#) f) /* s1) ) )assume that A4:
(
rng s1 c= X &
s1 is
convergent )
and A6:
lim s1 in X
;
( (r (#) f) /* s1 is convergent & (r (#) f) /. (lim s1) = lim ((r (#) f) /* s1) )A7:
f /* s1 is
convergent
by A1, A2, A4, A6, Th14;
then A8:
r * (f /* s1) is
convergent
by NORMSP_1:37;
f /. (lim s1) = lim (f /* s1)
by A1, A2, A4, A6, Th14;
then (r (#) f) /. (lim s1) =
r * (lim (f /* s1))
by A3, A6, VFUNCT_1:def 4
.=
lim (r * (f /* s1))
by A7, NORMSP_1:45
.=
lim ((r (#) f) /* s1)
by A1, A4, XTh20, XBOOLE_1:1
;
hence
(
(r (#) f) /* s1 is
convergent &
(r (#) f) /. (lim s1) = lim ((r (#) f) /* s1) )
by A1, A4, A8, XTh20, XBOOLE_1:1;
verum end;
hence
(r (#) f) | X is continuous
by A3, Th14; verum