let p be Rational; for s1, s2 being Real_Sequence st s1 is convergent & s2 is convergent & lim s1 > 0 & p >= 0 & ( for n being Nat holds
( s1 . n > 0 & s2 . n = (s1 . n) #Q p ) ) holds
lim s2 = (lim s1) #Q p
let s1, s2 be Real_Sequence; ( s1 is convergent & s2 is convergent & lim s1 > 0 & p >= 0 & ( for n being Nat holds
( s1 . n > 0 & s2 . n = (s1 . n) #Q p ) ) implies lim s2 = (lim s1) #Q p )
assume that
A1:
s1 is convergent
and
A2:
s2 is convergent
and
A3:
lim s1 > 0
and
A4:
p >= 0
and
A5:
for n being Nat holds
( s1 . n > 0 & s2 . n = (s1 . n) #Q p )
; lim s2 = (lim s1) #Q p
reconsider ls = lim s1 as Element of REAL by XREAL_0:def 1;
set s = seq_const (lim s1);
consider m0 being Nat such that
A6:
p < m0
by SEQ_4:3;
A7: lim (seq_const (lim s1)) =
(seq_const (lim s1)) . 0
by SEQ_4:26
.=
lim s1
by FUNCOP_1:7
;
then A8:
s1 /" (seq_const (lim s1)) is convergent
by A1, A3, SEQ_2:23;
deffunc H1( Nat) -> set = (((seq_const (lim s1)) /" s1) . $1) |^ m0;
consider s3 being Real_Sequence such that
A9:
for n being Nat holds s3 . n = H1(n)
from SEQ_1:sch 1();
for n being Nat holds s1 . n <> 0
by A5;
then A10:
s1 is non-zero
by SEQ_1:5;
then A11:
(seq_const (lim s1)) /" s1 is convergent
by A1, A3, SEQ_2:23;
then A12:
s3 is convergent
by A9, Th18;
reconsider q = m0 as Rational ;
deffunc H2( Nat) -> set = ((s1 /" (seq_const (lim s1))) . $1) |^ m0;
consider s4 being Real_Sequence such that
A13:
for n being Nat holds s4 . n = H2(n)
from SEQ_1:sch 1();
lim ((seq_const (lim s1)) /" s1) =
(lim (seq_const (lim s1))) / (lim s1)
by A1, A3, A10, SEQ_2:24
.=
1
by A3, A7, XCMPLX_1:60
;
then
lim s3 = 1 |^ m0
by A11, A9, Th18;
then A14:
lim s3 = 1
;
lim (s1 /" (seq_const (lim s1))) =
(lim s1) / (lim (seq_const (lim s1)))
by A1, A3, A7, SEQ_2:24
.=
1
by A3, A7, XCMPLX_1:60
;
then
lim s4 = 1 |^ m0
by A8, A13, Th18;
then A15:
lim s4 = 1
;
s2 is bounded
by A2;
then consider d being Real such that
A16:
d > 0
and
A17:
for n being Nat holds |.(s2 . n).| < d
by SEQ_2:3;
A18:
s4 is convergent
by A8, A13, Th18;
now for c being Real st c > 0 holds
ex n being set st
for m being Nat st m >= n holds
|.((s2 . m) - ((lim s1) #Q p)).| < clet c be
Real;
( c > 0 implies ex n being set st
for m being Nat st m >= n holds
|.((s2 . m) - ((lim s1) #Q p)).| < c )assume A19:
c > 0
;
ex n being set st
for m being Nat st m >= n holds
|.((s2 . m) - ((lim s1) #Q p)).| < cthen
c / d > 0
by A16;
then consider m1 being
Nat such that A20:
for
m being
Nat st
m >= m1 holds
|.((s3 . m) - 1).| < c / d
by A12, A14, SEQ_2:def 7;
A21:
(lim s1) #Q p > 0
by A3, Th52;
then A22:
|.((lim s1) #Q p).| > 0
by ABSVALUE:def 1;
then
c / |.((lim s1) #Q p).| > 0
by A19;
then consider m2 being
Nat such that A23:
for
m being
Nat st
m >= m2 holds
|.((s4 . m) - 1).| < c / |.((lim s1) #Q p).|
by A18, A15, SEQ_2:def 7;
take n =
m1 + m2;
for m being Nat st m >= n holds
|.((s2 . m) - ((lim s1) #Q p)).| < clet m be
Nat;
( m >= n implies |.((s2 . m) - ((lim s1) #Q p)).| < c )assume A24:
m >= n
;
|.((s2 . m) - ((lim s1) #Q p)).| < c
m2 <= n
by NAT_1:11;
then A25:
m >= m2
by A24, XXREAL_0:2;
m1 <= n
by NAT_1:11;
then A26:
m >= m1
by A24, XXREAL_0:2;
now |.((s2 . m) - ((lim s1) #Q p)).| < cper cases
( s1 . m >= lim s1 or s1 . m <= lim s1 )
;
suppose A27:
s1 . m >= lim s1
;
|.((s2 . m) - ((lim s1) #Q p)).| < c
m in NAT
by ORDINAL1:def 12;
then A28:
(s1 . m) / (lim s1) =
(s1 . m) / ((seq_const (lim s1)) . m)
by FUNCOP_1:7
.=
(s1 . m) * (((seq_const (lim s1)) . m) ")
.=
(s1 . m) * (((seq_const (lim s1)) ") . m)
by VALUED_1:10
.=
(s1 /" (seq_const (lim s1))) . m
by SEQ_1:8
;
(s1 . m) * ((lim s1) ") >= (lim s1) * ((lim s1) ")
by A3, A27, XREAL_1:64;
then A29:
(s1 /" (seq_const (lim s1))) . m >= 1
by A3, A28, XCMPLX_0:def 7;
then
((s1 /" (seq_const (lim s1))) . m) #Q p <= ((s1 /" (seq_const (lim s1))) . m) #Q q
by A6, Th63;
then
((s1 /" (seq_const (lim s1))) . m) #Q p <= ((s1 /" (seq_const (lim s1))) . m) |^ m0
by A29, Th49;
then A30:
(((s1 /" (seq_const (lim s1))) . m) #Q p) - 1
<= (((s1 /" (seq_const (lim s1))) . m) |^ m0) - 1
by XREAL_1:9;
((s1 /" (seq_const (lim s1))) . m) #Q p >= 1
by A4, A29, Th60;
then
(((s1 /" (seq_const (lim s1))) . m) #Q p) - 1
>= 1
- 1
by XREAL_1:9;
then A31:
(((s1 /" (seq_const (lim s1))) . m) #Q p) - 1
= |.((((s1 /" (seq_const (lim s1))) . m) #Q p) - 1).|
by ABSVALUE:def 1;
A32:
(lim s1) #Q p <> 0
by A3, Th52;
A33:
|.((s4 . m) - 1).| < c / |.((lim s1) #Q p).|
by A23, A25;
A34:
s1 . m > 0
by A5;
((s1 /" (seq_const (lim s1))) . m) |^ m0 >= 1
by A29, Th11;
then
(((s1 /" (seq_const (lim s1))) . m) |^ m0) - 1
>= 1
- 1
by XREAL_1:9;
then
|.((((s1 /" (seq_const (lim s1))) . m) #Q p) - 1).| <= |.((((s1 /" (seq_const (lim s1))) . m) |^ m0) - 1).|
by A30, A31, ABSVALUE:def 1;
then
|.((((s1 /" (seq_const (lim s1))) . m) #Q p) - 1).| <= |.((s4 . m) - 1).|
by A13;
then A35:
|.((((s1 /" (seq_const (lim s1))) . m) #Q p) - 1).| < c / |.((lim s1) #Q p).|
by A33, XXREAL_0:2;
A36:
|.((lim s1) #Q p).| <> 0
by A21, ABSVALUE:def 1;
|.((s2 . m) - ((lim s1) #Q p)).| =
|.((((s1 . m) #Q p) - ((lim s1) #Q p)) * 1).|
by A5
.=
|.((((s1 . m) #Q p) - ((lim s1) #Q p)) * (((lim s1) #Q p) / ((lim s1) #Q p))).|
by A32, XCMPLX_1:60
.=
|.((((lim s1) #Q p) * (((s1 . m) #Q p) - ((lim s1) #Q p))) / ((lim s1) #Q p)).|
.=
|.(((lim s1) #Q p) * ((((s1 . m) #Q p) - ((lim s1) #Q p)) / ((lim s1) #Q p))).|
.=
|.((lim s1) #Q p).| * |.((((s1 . m) #Q p) - ((lim s1) #Q p)) / ((lim s1) #Q p)).|
by COMPLEX1:65
.=
|.((lim s1) #Q p).| * |.((((s1 . m) #Q p) / ((lim s1) #Q p)) - (((lim s1) #Q p) / ((lim s1) #Q p))).|
.=
|.((lim s1) #Q p).| * |.((((s1 . m) #Q p) / ((lim s1) #Q p)) - 1).|
by A32, XCMPLX_1:60
.=
|.((lim s1) #Q p).| * |.((((s1 . m) / (lim s1)) #Q p) - 1).|
by A3, A34, Th58
;
then
|.((s2 . m) - ((lim s1) #Q p)).| < |.((lim s1) #Q p).| * (c / |.((lim s1) #Q p).|)
by A22, A28, A35, XREAL_1:68;
hence
|.((s2 . m) - ((lim s1) #Q p)).| < c
by A36, XCMPLX_1:87;
verum end; suppose A37:
s1 . m <= lim s1
;
|.((s2 . m) - ((lim s1) #Q p)).| < cA38:
m in NAT
by ORDINAL1:def 12;
A39:
(lim s1) / (s1 . m) =
((seq_const (lim s1)) . m) / (s1 . m)
by FUNCOP_1:7, A38
.=
((seq_const (lim s1)) . m) * ((s1 . m) ")
.=
((seq_const (lim s1)) . m) * ((s1 ") . m)
by VALUED_1:10
.=
((seq_const (lim s1)) /" s1) . m
by SEQ_1:8
;
A40:
s1 . m <> 0
by A5;
A41:
s1 . m > 0
by A5;
then
(s1 . m) * ((s1 . m) ") <= (lim s1) * ((s1 . m) ")
by A37, XREAL_1:64;
then A42:
((seq_const (lim s1)) /" s1) . m >= 1
by A40, A39, XCMPLX_0:def 7;
then
(((seq_const (lim s1)) /" s1) . m) #Q p <= (((seq_const (lim s1)) /" s1) . m) #Q q
by A6, Th63;
then
(((seq_const (lim s1)) /" s1) . m) #Q p <= (((seq_const (lim s1)) /" s1) . m) |^ m0
by A42, Th49;
then A43:
((((seq_const (lim s1)) /" s1) . m) #Q p) - 1
<= ((((seq_const (lim s1)) /" s1) . m) |^ m0) - 1
by XREAL_1:9;
(s1 . m) #Q p > 0
by A5, Th52;
then A44:
|.((s1 . m) #Q p).| > 0
by ABSVALUE:def 1;
A45:
|.((s3 . m) - 1).| < c / d
by A20, A26;
(((seq_const (lim s1)) /" s1) . m) #Q p >= 1
by A4, A42, Th60;
then
((((seq_const (lim s1)) /" s1) . m) #Q p) - 1
>= 1
- 1
by XREAL_1:9;
then A46:
((((seq_const (lim s1)) /" s1) . m) #Q p) - 1
= |.(((((seq_const (lim s1)) /" s1) . m) #Q p) - 1).|
by ABSVALUE:def 1;
(((seq_const (lim s1)) /" s1) . m) |^ m0 >= 1
by A42, Th11;
then
((((seq_const (lim s1)) /" s1) . m) |^ m0) - 1
>= 1
- 1
by XREAL_1:9;
then
|.(((((seq_const (lim s1)) /" s1) . m) #Q p) - 1).| <= |.(((((seq_const (lim s1)) /" s1) . m) |^ m0) - 1).|
by A43, A46, ABSVALUE:def 1;
then
|.(((((seq_const (lim s1)) /" s1) . m) #Q p) - 1).| <= |.((s3 . m) - 1).|
by A9;
then A47:
|.(((((seq_const (lim s1)) /" s1) . m) #Q p) - 1).| < c / d
by A45, XXREAL_0:2;
|.(s2 . m).| < d
by A17;
then
|.((s1 . m) #Q p).| < d
by A5;
then
|.((s1 . m) #Q p).| / d < d / d
by A16, XREAL_1:74;
then
|.((s1 . m) #Q p).| / d < 1
by A16, XCMPLX_1:60;
then A48:
c * (|.((s1 . m) #Q p).| / d) < c * 1
by A19, XREAL_1:68;
A49:
(s1 . m) #Q p <> 0
by A5, Th52;
|.((s2 . m) - ((lim s1) #Q p)).| =
|.((((s1 . m) #Q p) - ((lim s1) #Q p)) * 1).|
by A5
.=
|.((((s1 . m) #Q p) - ((lim s1) #Q p)) * (((s1 . m) #Q p) / ((s1 . m) #Q p))).|
by A49, XCMPLX_1:60
.=
|.((((s1 . m) #Q p) * (((s1 . m) #Q p) - ((lim s1) #Q p))) / ((s1 . m) #Q p)).|
.=
|.(((s1 . m) #Q p) * ((((s1 . m) #Q p) - ((lim s1) #Q p)) / ((s1 . m) #Q p))).|
.=
|.((s1 . m) #Q p).| * |.((((s1 . m) #Q p) - ((lim s1) #Q p)) / ((s1 . m) #Q p)).|
by COMPLEX1:65
.=
|.((s1 . m) #Q p).| * |.((((s1 . m) #Q p) / ((s1 . m) #Q p)) - (((lim s1) #Q p) / ((s1 . m) #Q p))).|
.=
|.((s1 . m) #Q p).| * |.(1 - (((lim s1) #Q p) / ((s1 . m) #Q p))).|
by A49, XCMPLX_1:60
.=
|.((s1 . m) #Q p).| * |.(- (1 - (((lim s1) #Q p) / ((s1 . m) #Q p)))).|
by COMPLEX1:52
.=
|.((s1 . m) #Q p).| * |.((((lim s1) #Q p) / ((s1 . m) #Q p)) - 1).|
.=
|.((s1 . m) #Q p).| * |.((((lim s1) / (s1 . m)) #Q p) - 1).|
by A3, A41, Th58
;
then
|.((s2 . m) - ((lim s1) #Q p)).| < |.((s1 . m) #Q p).| * (c / d)
by A44, A39, A47, XREAL_1:68;
hence
|.((s2 . m) - ((lim s1) #Q p)).| < c
by A48, XXREAL_0:2;
verum end; end; end; hence
|.((s2 . m) - ((lim s1) #Q p)).| < c
;
verum end;
hence
lim s2 = (lim s1) #Q p
by A2, SEQ_2:def 7; verum