let X be RealBanachSpace; for X0 being Subset of (LinearTopSpaceNorm X)
for Y being RealBanachSpace
for vseq being sequence of (R_NormSpace_of_BoundedLinearOperators (X,Y)) st X0 is dense & ( for x being Point of X st x in X0 holds
vseq # x is convergent ) & ( for x being Point of X ex K being Real st
( 0 <= K & ( for n being Nat holds ||.((vseq # x) . n).|| <= K ) ) ) holds
for x being Point of X holds vseq # x is convergent
let X0 be Subset of (LinearTopSpaceNorm X); for Y being RealBanachSpace
for vseq being sequence of (R_NormSpace_of_BoundedLinearOperators (X,Y)) st X0 is dense & ( for x being Point of X st x in X0 holds
vseq # x is convergent ) & ( for x being Point of X ex K being Real st
( 0 <= K & ( for n being Nat holds ||.((vseq # x) . n).|| <= K ) ) ) holds
for x being Point of X holds vseq # x is convergent
let Y be RealBanachSpace; for vseq being sequence of (R_NormSpace_of_BoundedLinearOperators (X,Y)) st X0 is dense & ( for x being Point of X st x in X0 holds
vseq # x is convergent ) & ( for x being Point of X ex K being Real st
( 0 <= K & ( for n being Nat holds ||.((vseq # x) . n).|| <= K ) ) ) holds
for x being Point of X holds vseq # x is convergent
let vseq be sequence of (R_NormSpace_of_BoundedLinearOperators (X,Y)); ( X0 is dense & ( for x being Point of X st x in X0 holds
vseq # x is convergent ) & ( for x being Point of X ex K being Real st
( 0 <= K & ( for n being Nat holds ||.((vseq # x) . n).|| <= K ) ) ) implies for x being Point of X holds vseq # x is convergent )
assume A1:
X0 is dense
; ( ex x being Point of X st
( x in X0 & not vseq # x is convergent ) or ex x being Point of X st
for K being Real holds
( not 0 <= K or ex n being Nat st not ||.((vseq # x) . n).|| <= K ) or for x being Point of X holds vseq # x is convergent )
set T = rng vseq;
assume A2:
for x being Point of X st x in X0 holds
vseq # x is convergent
; ( ex x being Point of X st
for K being Real holds
( not 0 <= K or ex n being Nat st not ||.((vseq # x) . n).|| <= K ) or for x being Point of X holds vseq # x is convergent )
vseq in Funcs (NAT, the carrier of (R_NormSpace_of_BoundedLinearOperators (X,Y)))
by FUNCT_2:8;
then
ex f0 being Function st
( vseq = f0 & dom f0 = NAT & rng f0 c= the carrier of (R_NormSpace_of_BoundedLinearOperators (X,Y)) )
by FUNCT_2:def 2;
then reconsider T = rng vseq as Subset of (R_NormSpace_of_BoundedLinearOperators (X,Y)) ;
assume A3:
for x being Point of X ex K being Real st
( 0 <= K & ( for n being Nat holds ||.((vseq # x) . n).|| <= K ) )
; for x being Point of X holds vseq # x is convergent
for x being Point of X ex K being Real st
( 0 <= K & ( for f being Point of (R_NormSpace_of_BoundedLinearOperators (X,Y)) st f in T holds
||.(f . x).|| <= K ) )
then consider L being Real such that
A8:
0 <= L
and
A9:
for f being Point of (R_NormSpace_of_BoundedLinearOperators (X,Y)) st f in T holds
||.f.|| <= L
by Th5;
set M = 1 + L;
A10:
L + 0 < 1 + L
by XREAL_1:8;
A11:
for f being Lipschitzian LinearOperator of X,Y st f in T holds
for x, y being Point of X holds ||.((f . x) - (f . y)).|| <= (1 + L) * ||.(x - y).||
hereby verum
let x be
Point of
X;
vseq # x is convergent
for
TK1 being
Real st
TK1 > 0 holds
ex
n0 being
Nat st
for
n,
m being
Nat st
n >= n0 &
m >= n0 holds
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
proof
let TK1 be
Real;
( TK1 > 0 implies ex n0 being Nat st
for n, m being Nat st n >= n0 & m >= n0 holds
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1 )
assume A14:
TK1 > 0
;
ex n0 being Nat st
for n, m being Nat st n >= n0 & m >= n0 holds
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
A15:
0 < TK1 / 3
by A14, XREAL_1:222;
set V =
{ z where z is Point of X : ||.(x - z).|| < TK1 / (3 * (1 + L)) } ;
{ z where z is Point of X : ||.(x - z).|| < TK1 / (3 * (1 + L)) } c= the
carrier of
X
then reconsider V =
{ z where z is Point of X : ||.(x - z).|| < TK1 / (3 * (1 + L)) } as
Subset of
(LinearTopSpaceNorm X) by NORMSP_2:def 4;
reconsider TKK =
TK1 as
Real ;
0 < 3
* (1 + L)
by A8, XREAL_1:129;
then
0 < TK1 / (3 * (1 + L))
by A14, XREAL_1:139;
then
||.(x - x).|| < TKK / (3 * (1 + L))
by NORMSP_1:6;
then
(
V is
open &
x in V )
by NORMSP_2:23;
then
X0 meets V
by A1, TOPS_1:45;
then consider s being
object such that A16:
s in X0
and A17:
s in V
by XBOOLE_0:3;
consider y being
Point of
X such that A18:
s = y
and A19:
||.(x - y).|| < TK1 / (3 * (1 + L))
by A17;
for
s being
Real st
0 < s holds
ex
n1 being
Nat st
for
m1 being
Nat st
n1 <= m1 holds
||.(((vseq # y) . m1) - ((vseq # y) . n1)).|| < s
by A2, A16, A18, LOPBAN_3:4;
then
vseq # y is
Cauchy_sequence_by_Norm
by LOPBAN_3:5;
then consider n0 being
Nat such that A20:
for
n,
m being
Nat st
n >= n0 &
m >= n0 holds
||.(((vseq # y) . n) - ((vseq # y) . m)).|| < TK1 / 3
by A15, RSSPACE3:8;
take
n0
;
for n, m being Nat st n >= n0 & m >= n0 holds
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
for
n,
m being
Nat st
n >= n0 &
m >= n0 holds
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
proof
let n,
m be
Nat;
( n >= n0 & m >= n0 implies ||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1 )
A21:
m in NAT
by ORDINAL1:def 12;
A22:
n in NAT
by ORDINAL1:def 12;
reconsider f =
vseq . n as
Lipschitzian LinearOperator of
X,
Y by LOPBAN_1:def 9;
reconsider g =
vseq . m as
Lipschitzian LinearOperator of
X,
Y by LOPBAN_1:def 9;
||.(((vseq # x) . n) - ((vseq # y) . m)).|| <= ||.(((vseq # x) . n) - ((vseq # y) . n)).|| + ||.(((vseq # y) . n) - ((vseq # y) . m)).||
by NORMSP_1:10;
then A23:
||.(((vseq # x) . n) - ((vseq # y) . m)).|| + ||.(((vseq # y) . m) - ((vseq # x) . m)).|| <= (||.(((vseq # x) . n) - ((vseq # y) . n)).|| + ||.(((vseq # y) . n) - ((vseq # y) . m)).||) + ||.(((vseq # y) . m) - ((vseq # x) . m)).||
by XREAL_1:6;
assume
(
n >= n0 &
m >= n0 )
;
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
then
||.(((vseq # y) . n) - ((vseq # y) . m)).|| < TK1 / 3
by A20;
then
||.(((vseq # x) . n) - ((vseq # y) . n)).|| + ||.(((vseq # y) . n) - ((vseq # y) . m)).|| < ||.(((vseq # x) . n) - ((vseq # y) . n)).|| + (TK1 / 3)
by XREAL_1:8;
then A24:
(||.(((vseq # x) . n) - ((vseq # y) . n)).|| + ||.(((vseq # y) . n) - ((vseq # y) . m)).||) + ||.(((vseq # y) . m) - ((vseq # x) . m)).|| < (||.(((vseq # x) . n) - ((vseq # y) . n)).|| + (TK1 / 3)) + ||.(((vseq # y) . m) - ((vseq # x) . m)).||
by XREAL_1:8;
||.(((vseq # x) . m) - ((vseq # y) . m)).|| = ||.(((vseq . m) . x) - ((vseq # y) . m)).||
by Def2;
then
||.(((vseq # x) . m) - ((vseq # y) . m)).|| = ||.((g . x) - (g . y)).||
by Def2;
then A25:
||.(((vseq # x) . m) - ((vseq # y) . m)).|| <= (1 + L) * ||.(x - y).||
by A11, FUNCT_2:4, A21;
(1 + L) * ||.(x - y).|| < (1 + L) * (TK1 / (3 * (1 + L)))
by A8, A19, XREAL_1:68;
then
(1 + L) * ||.(x - y).|| < TK1 / 3
by A8, XCMPLX_1:92;
then
||.(((vseq # x) . m) - ((vseq # y) . m)).|| < TK1 / 3
by A25, XXREAL_0:2;
then
||.(((vseq # y) . m) - ((vseq # x) . m)).|| < TK1 / 3
by NORMSP_1:7;
then A26:
((TK1 / 3) + (TK1 / 3)) + ||.(((vseq # y) . m) - ((vseq # x) . m)).|| < ((TK1 / 3) + (TK1 / 3)) + (TK1 / 3)
by XREAL_1:8;
||.(((vseq # x) . n) - ((vseq # y) . n)).|| = ||.(((vseq . n) . x) - ((vseq # y) . n)).||
by Def2;
then
||.(((vseq # x) . n) - ((vseq # y) . n)).|| = ||.((f . x) - (f . y)).||
by Def2;
then A27:
||.(((vseq # x) . n) - ((vseq # y) . n)).|| <= (1 + L) * ||.(x - y).||
by A11, FUNCT_2:4, A22;
||.(((vseq # x) . n) - ((vseq # x) . m)).|| <= ||.(((vseq # x) . n) - ((vseq # y) . m)).|| + ||.(((vseq # y) . m) - ((vseq # x) . m)).||
by NORMSP_1:10;
then
||.(((vseq # x) . n) - ((vseq # x) . m)).|| <= (||.(((vseq # x) . n) - ((vseq # y) . n)).|| + ||.(((vseq # y) . n) - ((vseq # y) . m)).||) + ||.(((vseq # y) . m) - ((vseq # x) . m)).||
by A23, XXREAL_0:2;
then A28:
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < (||.(((vseq # x) . n) - ((vseq # y) . n)).|| + (TK1 / 3)) + ||.(((vseq # y) . m) - ((vseq # x) . m)).||
by A24, XXREAL_0:2;
(1 + L) * ||.(x - y).|| < (1 + L) * (TK1 / (3 * (1 + L)))
by A8, A19, XREAL_1:68;
then
(1 + L) * ||.(x - y).|| < TK1 / 3
by A8, XCMPLX_1:92;
then
||.(((vseq # x) . n) - ((vseq # y) . n)).|| < TK1 / 3
by A27, XXREAL_0:2;
then
||.(((vseq # x) . n) - ((vseq # y) . n)).|| + (TK1 / 3) < (TK1 / 3) + (TK1 / 3)
by XREAL_1:8;
then
(||.(((vseq # x) . n) - ((vseq # y) . n)).|| + (TK1 / 3)) + ||.(((vseq # y) . m) - ((vseq # x) . m)).|| < ((TK1 / 3) + (TK1 / 3)) + ||.(((vseq # y) . m) - ((vseq # x) . m)).||
by XREAL_1:8;
then
(||.(((vseq # x) . n) - ((vseq # y) . n)).|| + (TK1 / 3)) + ||.(((vseq # y) . m) - ((vseq # x) . m)).|| < ((TK1 / 3) + (TK1 / 3)) + (TK1 / 3)
by A26, XXREAL_0:2;
hence
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
by A28, XXREAL_0:2;
verum
end;
hence
for
n,
m being
Nat st
n >= n0 &
m >= n0 holds
||.(((vseq # x) . n) - ((vseq # x) . m)).|| < TK1
;
verum
end; then
vseq # x is
Cauchy_sequence_by_Norm
by RSSPACE3:8;
hence
vseq # x is
convergent
by LOPBAN_1:def 15;
verum
end;