let D be non empty set ; for H being Functional_Sequence of D,REAL
for X, Y being set st Y c= X & Y <> {} & H is_point_conv_on X holds
( H is_point_conv_on Y & (lim (H,X)) | Y = lim (H,Y) )
let H be Functional_Sequence of D,REAL; for X, Y being set st Y c= X & Y <> {} & H is_point_conv_on X holds
( H is_point_conv_on Y & (lim (H,X)) | Y = lim (H,Y) )
let X, Y be set ; ( Y c= X & Y <> {} & H is_point_conv_on X implies ( H is_point_conv_on Y & (lim (H,X)) | Y = lim (H,Y) ) )
assume that
A1:
Y c= X
and
A2:
Y <> {}
and
A3:
H is_point_conv_on X
; ( H is_point_conv_on Y & (lim (H,X)) | Y = lim (H,Y) )
consider f being PartFunc of D,REAL such that
A4:
X = dom f
and
A5:
for x being Element of D st x in X holds
for p being Real st p > 0 holds
ex k being Nat st
for n being Nat st n >= k holds
|.(((H . n) . x) - (f . x)).| < p
by A3;
X common_on_dom H
by A3;
then
Y common_on_dom H
by A1, A2, Th22;
hence A10:
H is_point_conv_on Y
by A6; (lim (H,X)) | Y = lim (H,Y)
A11:
now for x being Element of D st x in dom ((lim (H,X)) | Y) holds
((lim (H,X)) | Y) . x = (lim (H,Y)) . xlet x be
Element of
D;
( x in dom ((lim (H,X)) | Y) implies ((lim (H,X)) | Y) . x = (lim (H,Y)) . x )assume A12:
x in dom ((lim (H,X)) | Y)
;
((lim (H,X)) | Y) . x = (lim (H,Y)) . xthen A13:
x in (dom (lim (H,X))) /\ Y
by RELAT_1:61;
then A14:
x in dom (lim (H,X))
by XBOOLE_0:def 4;
x in Y
by A13, XBOOLE_0:def 4;
then A15:
x in dom (lim (H,Y))
by A10, Def13;
thus ((lim (H,X)) | Y) . x =
(lim (H,X)) . x
by A12, FUNCT_1:47
.=
lim (H # x)
by A3, A14, Def13
.=
(lim (H,Y)) . x
by A10, A15, Def13
;
verum end;
dom (lim (H,X)) = X
by A3, Def13;
then
(dom (lim (H,X))) /\ Y = Y
by A1, XBOOLE_1:28;
then
dom ((lim (H,X)) | Y) = Y
by RELAT_1:61;
then
dom ((lim (H,X)) | Y) = dom (lim (H,Y))
by A10, Def13;
hence
(lim (H,X)) | Y = lim (H,Y)
by A11, PARTFUN1:5; verum