let T be non empty TopSpace; for F being Functional_Sequence of the carrier of T,REAL st F is_unif_conv_on the carrier of T & ( for i being Element of NAT holds F . i is continuous Function of T,R^1 ) holds
lim (F, the carrier of T) is continuous Function of T,R^1
let F be Functional_Sequence of the carrier of T,REAL; ( F is_unif_conv_on the carrier of T & ( for i being Element of NAT holds F . i is continuous Function of T,R^1 ) implies lim (F, the carrier of T) is continuous Function of T,R^1 )
assume that
A1:
F is_unif_conv_on the carrier of T
and
A2:
for i being Element of NAT holds F . i is continuous Function of T,R^1
; lim (F, the carrier of T) is continuous Function of T,R^1
F is_point_conv_on the carrier of T
by A1, SEQFUNC:43;
then
dom (lim (F, the carrier of T)) = the carrier of T
by SEQFUNC:def 13;
then reconsider l = lim (F, the carrier of T) as Function of T,R^1 by FUNCT_2:def 1, TOPMETR:17;
now let p be
Point of
T;
l is_continuous_at pnow let e be
real number ;
( e > 0 implies ex H being Subset of T st
( H is open & p in H & ( for y being Point of T st y in H holds
abs ((l . y) - (l . p)) < e ) ) )assume A3:
e > 0
;
ex H being Subset of T st
( H is open & p in H & ( for y being Point of T st y in H holds
abs ((l . y) - (l . p)) < e ) )reconsider e3 =
e / 3 as
Real ;
A4:
e3 > 0
by A3, XREAL_1:139;
then consider k being
Element of
NAT such that A5:
for
n being
Element of
NAT for
x being
Point of
T st
n >= k &
x in the
carrier of
T holds
abs (((F . n) . x) - ((lim (F, the carrier of T)) . x)) < e3
by A1, SEQFUNC:43;
reconsider Fk =
F . k as
continuous Function of
T,
R^1 by A2;
A6:
abs ((Fk . p) - (l . p)) < e3
by A5;
Fk is_continuous_at p
by TMAP_1:44;
then consider H being
Subset of
T such that A7:
(
H is
open &
p in H )
and A8:
for
y being
Point of
T st
y in H holds
abs ((Fk . y) - (Fk . p)) < e3
by A4, Th21;
take H =
H;
( H is open & p in H & ( for y being Point of T st y in H holds
abs ((l . y) - (l . p)) < e ) )thus
(
H is
open &
p in H )
by A7;
for y being Point of T st y in H holds
abs ((l . y) - (l . p)) < elet y be
Point of
T;
( y in H implies abs ((l . y) - (l . p)) < e )assume A9:
y in H
;
abs ((l . y) - (l . p)) < e
abs ((Fk . y) - (l . y)) < e3
by A5;
then
abs (- ((Fk . y) - (l . y))) < e3
by COMPLEX1:52;
then
(
abs (((Fk . p) - (l . p)) + ((- (Fk . y)) + (l . y))) <= (abs ((Fk . p) - (l . p))) + (abs (- ((Fk . y) - (l . y)))) &
(abs ((Fk . p) - (l . p))) + (abs (- ((Fk . y) - (l . y)))) < e3 + e3 )
by A6, COMPLEX1:56, XREAL_1:8;
then
abs (((Fk . p) - (l . p)) + ((- (Fk . y)) + (l . y))) < 2
* e3
by XXREAL_0:2;
then
(
abs (((Fk . y) - (Fk . p)) + (((Fk . p) - (l . p)) + ((- (Fk . y)) + (l . y)))) <= (abs ((Fk . y) - (Fk . p))) + (abs (((Fk . p) - (l . p)) + ((- (Fk . y)) + (l . y)))) &
(abs ((Fk . y) - (Fk . p))) + (abs (((Fk . p) - (l . p)) + ((- (Fk . y)) + (l . y)))) < e3 + (2 * e3) )
by A8, A9, COMPLEX1:56, XREAL_1:8;
hence
abs ((l . y) - (l . p)) < e
by XXREAL_0:2;
verum end; hence
l is_continuous_at p
by Th21;
verum end;
hence
lim (F, the carrier of T) is continuous Function of T,R^1
by TMAP_1:44; verum