let S be non empty TopSpace; for T being NormedLinearTopSpace
for H being Functional_Sequence of the carrier of S, the carrier of T
for LimH being Function of S,T st H is_unif_conv_on the carrier of S & ( for n being Nat ex Hn being Function of S,T st
( Hn = H . n & Hn is continuous ) ) & LimH = lim (H, the carrier of S) holds
LimH is continuous
let T be NormedLinearTopSpace; for H being Functional_Sequence of the carrier of S, the carrier of T
for LimH being Function of S,T st H is_unif_conv_on the carrier of S & ( for n being Nat ex Hn being Function of S,T st
( Hn = H . n & Hn is continuous ) ) & LimH = lim (H, the carrier of S) holds
LimH is continuous
let H be Functional_Sequence of the carrier of S, the carrier of T; for LimH being Function of S,T st H is_unif_conv_on the carrier of S & ( for n being Nat ex Hn being Function of S,T st
( Hn = H . n & Hn is continuous ) ) & LimH = lim (H, the carrier of S) holds
LimH is continuous
let LimH be Function of S,T; ( H is_unif_conv_on the carrier of S & ( for n being Nat ex Hn being Function of S,T st
( Hn = H . n & Hn is continuous ) ) & LimH = lim (H, the carrier of S) implies LimH is continuous )
assume that
A1:
H is_unif_conv_on the carrier of S
and
A2:
for n being Nat ex Hn being Function of S,T st
( Hn = H . n & Hn is continuous )
and
A3:
LimH = lim (H, the carrier of S)
; LimH is continuous
set X = the carrier of S;
A4:
H is_point_conv_on the carrier of S
by A1, SEQFUNC2:33;
for x being Point of S holds LimH is_continuous_at x
proof
let x be
Point of
S;
LimH is_continuous_at x
for
G being
a_neighborhood of
LimH . x ex
H being
a_neighborhood of
x st
LimH .: H c= G
proof
let G be
a_neighborhood of
LimH . x;
ex H being a_neighborhood of x st LimH .: H c= G
consider r being
Real such that A5:
(
r > 0 &
{ y where y is Point of T : ||.(y - (LimH . x)).|| < r } c= G )
by Th30;
A6:
0 < r / 3
by XREAL_1:222, A5;
reconsider r =
r as
Element of
REAL by XREAL_0:def 1;
consider k being
Nat such that A7:
for
n being
Nat for
x1 being
Element of
S st
n >= k &
x1 in the
carrier of
S holds
||.(((H . n) /. x1) - (LimH /. x1)).|| < r / 3
by A1, XREAL_1:222, A5, A3, SEQFUNC2:33;
consider k1 being
Nat such that A8:
for
n being
Nat st
n >= k1 holds
||.(((H . n) /. x) - (LimH /. x)).|| < r / 3
by A4, A6, A3, SEQFUNC2:11;
reconsider m =
max (
k,
k1) as
Nat by XXREAL_0:def 10;
consider h being
Function of
S,
T such that A9:
(
h = H . m &
h is
continuous )
by A2;
set W =
{ y where y is Point of T : ||.(y - (h . x)).|| < r / 3 } ;
then reconsider W =
{ y where y is Point of T : ||.(y - (h . x)).|| < r / 3 } as
Subset of
T by TARSKI:def 3;
W is
a_neighborhood of
h . x
by XREAL_1:222, A5, Th30;
then consider H being
a_neighborhood of
x such that A10:
h .: H c= W
by A9, TMAP_1:44, TMAP_1:def 2;
take
H
;
LimH .: H c= G
now for z being object st z in LimH .: H holds
z in Glet z be
object ;
( z in LimH .: H implies z in G )assume
z in LimH .: H
;
z in Gthen consider s being
object such that A11:
(
s in the
carrier of
S &
s in H &
z = LimH . s )
by FUNCT_2:64;
reconsider s =
s as
Point of
S by A11;
h . s in h .: H
by A11, FUNCT_2:35;
then
h . s in W
by A10;
then A12:
ex
y being
Point of
T st
(
y = h . s &
||.(y - (h . x)).|| < r / 3 )
;
||.((h /. s) - (LimH /. s)).|| < r / 3
by A7, A9, XXREAL_0:25;
then A13:
||.((LimH /. s) - (h /. s)).|| < r / 3
by NORMSP_1:7;
A14:
||.((h /. x) - (LimH /. x)).|| < r / 3
by A8, A9, XXREAL_0:25;
(LimH . s) - (LimH . x) =
(((LimH . s) - (h /. s)) + (h /. s)) - (LimH . x)
by RLVECT_4:1
.=
((LimH . s) - (h /. s)) + ((h /. s) - (LimH . x))
by RLVECT_1:28
.=
((LimH . s) - (h /. s)) + ((((h /. s) - (h /. x)) + (h /. x)) - (LimH . x))
by RLVECT_4:1
.=
((LimH . s) - (h /. s)) + (((h /. s) - (h /. x)) + ((h /. x) - (LimH . x)))
by RLVECT_1:28
;
then A15:
||.((LimH . s) - (LimH . x)).|| <= ||.((LimH . s) - (h /. s)).|| + ||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).||
by NORMSP_1:def 1;
A16:
||.((LimH . s) - (h /. s)).|| + ||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).|| < (r / 3) + ||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).||
by XREAL_1:8, A13;
A17:
||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).|| <= ||.((h /. s) - (h /. x)).|| + ||.((h /. x) - (LimH . x)).||
by NORMSP_1:def 1;
||.((h /. s) - (h /. x)).|| + ||.((h /. x) - (LimH . x)).|| < (r / 3) + (r / 3)
by XREAL_1:8, A12, A14;
then
||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).|| < (r / 3) + (r / 3)
by A17, XXREAL_0:2;
then
(r / 3) + ||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).|| < (r / 3) + ((r / 3) + (r / 3))
by XREAL_1:8;
then
||.((LimH . s) - (h /. s)).|| + ||.(((h /. s) - (h /. x)) + ((h /. x) - (LimH . x))).|| < r
by A16, XXREAL_0:2;
then
||.((LimH . s) - (LimH . x)).|| < r
by A15, XXREAL_0:2;
then
LimH . s in { y where y is Point of T : ||.(y - (LimH . x)).|| < r }
;
hence
z in G
by A11, A5;
verum end;
hence
LimH .: H c= G
;
verum
end;
hence
LimH is_continuous_at x
by TMAP_1:def 2;
verum
end;
hence
LimH is continuous
by TMAP_1:44; verum