let s1, s2 be Rational_Sequence; for a being Real st s1 is convergent & s2 is convergent & lim s1 = lim s2 & a >= 1 holds
lim (a #Q s1) = lim (a #Q s2)
let a be Real; ( s1 is convergent & s2 is convergent & lim s1 = lim s2 & a >= 1 implies lim (a #Q s1) = lim (a #Q s2) )
assume that
A1:
s1 is convergent
and
A2:
s2 is convergent
and
A3:
lim s1 = lim s2
and
A4:
a >= 1
; lim (a #Q s1) = lim (a #Q s2)
A5:
s1 - s2 is convergent
by A1, A2;
A6:
a #Q s2 is convergent
by A2, A4, Th69;
s2 is bounded
by A2;
then consider d being Real such that
0 < d
and
A8:
for n being Nat holds |.(s2 . n).| < d
by SEQ_2:3;
consider m2 being Nat such that
A9:
d < m2
by SEQ_4:3;
reconsider m2 = m2 as Rational ;
A10: lim (s1 - s2) =
(lim s1) - (lim s2)
by A1, A2, SEQ_2:12
.=
0
by A3
;
A11:
now for c being Real st c > 0 holds
ex n being Nat st
for m being Nat st m >= n holds
|.((((a #Q s1) - (a #Q s2)) . m) - 0).| < cA12:
a #Q m2 >= 0
by A4, Th52;
let c be
Real;
( c > 0 implies ex n being Nat st
for m being Nat st m >= n holds
|.((((a #Q s1) - (a #Q s2)) . m) - 0).| < c )assume A13:
c > 0
;
ex n being Nat st
for m being Nat st m >= n holds
|.((((a #Q s1) - (a #Q s2)) . m) - 0).| < cconsider m1 being
Nat such that A14:
((a #Q m2) * (a - 1)) / c < m1
by SEQ_4:3;
m1 + 1
>= m1
by XREAL_1:29;
then
((a #Q m2) * (a - 1)) / c < m1 + 1
by A14, XXREAL_0:2;
then
(((a #Q m2) * (a - 1)) / c) * c < c * (m1 + 1)
by A13, XREAL_1:68;
then
(a #Q m2) * (a - 1) < c * (m1 + 1)
by A13, XCMPLX_1:87;
then
((a #Q m2) * (a - 1)) / (m1 + 1) < ((m1 + 1) * c) / (m1 + 1)
by XREAL_1:74;
then
((a #Q m2) * (a - 1)) / (m1 + 1) < (c / (m1 + 1)) * (m1 + 1)
;
then A15:
((a #Q m2) * (a - 1)) / (m1 + 1) < c
by XCMPLX_1:87;
consider n being
Nat such that A16:
for
m being
Nat st
n <= m holds
|.(((s1 - s2) . m) - 0).| < (m1 + 1) "
by A5, A10, SEQ_2:def 7;
take n =
n;
for m being Nat st m >= n holds
|.((((a #Q s1) - (a #Q s2)) . m) - 0).| < clet m be
Nat;
( m >= n implies |.((((a #Q s1) - (a #Q s2)) . m) - 0).| < c )assume
m >= n
;
|.((((a #Q s1) - (a #Q s2)) . m) - 0).| < cthen
|.(((s1 - s2) . m) - 0).| < (m1 + 1) "
by A16;
then A17:
|.((s1 . m) - (s2 . m)).| <= (m1 + 1) "
by RFUNCT_2:1;
A18:
m1 + 1
>= 0 + 1
by NAT_1:13;
then
((m1 + 1) -Root a) - 1
<= (a - 1) / (m1 + 1)
by A4, Th31;
then A19:
(a #Q m2) * (((m1 + 1) -Root a) - 1) <= (a #Q m2) * ((a - 1) / (m1 + 1))
by A12, XREAL_1:64;
A20:
a #Q (s2 . m) <> 0
by A4, Th52;
A21:
|.((a #Q (s1 . m)) - (a #Q (s2 . m))).| =
|.(((a #Q (s1 . m)) - (a #Q (s2 . m))) * 1).|
.=
|.(((a #Q (s1 . m)) - (a #Q (s2 . m))) * ((a #Q (s2 . m)) / (a #Q (s2 . m)))).|
by A20, XCMPLX_1:60
.=
|.(((a #Q (s2 . m)) * ((a #Q (s1 . m)) - (a #Q (s2 . m)))) / (a #Q (s2 . m))).|
.=
|.((a #Q (s2 . m)) * (((a #Q (s1 . m)) - (a #Q (s2 . m))) / (a #Q (s2 . m)))).|
.=
|.(a #Q (s2 . m)).| * |.(((a #Q (s1 . m)) - (a #Q (s2 . m))) / (a #Q (s2 . m))).|
by COMPLEX1:65
.=
|.(a #Q (s2 . m)).| * |.(((a #Q (s1 . m)) / (a #Q (s2 . m))) - ((a #Q (s2 . m)) / (a #Q (s2 . m)))).|
.=
|.(a #Q (s2 . m)).| * |.(((a #Q (s1 . m)) / (a #Q (s2 . m))) - 1).|
by A20, XCMPLX_1:60
.=
|.(a #Q (s2 . m)).| * |.((a #Q ((s1 . m) - (s2 . m))) - 1).|
by A4, Th55
;
A22:
s2 . m <= |.(s2 . m).|
by ABSVALUE:4;
reconsider m3 =
(m1 + 1) " as
Rational ;
A23:
|.((a #Q ((s1 . m) - (s2 . m))) - 1).| >= 0
by COMPLEX1:46;
A24:
a #Q ((s1 . m) - (s2 . m)) <> 0
by A4, Th52;
(s1 . m) - (s2 . m) <= |.((s1 . m) - (s2 . m)).|
by ABSVALUE:4;
then
(s1 . m) - (s2 . m) <= (m1 + 1) "
by A17, XXREAL_0:2;
then
a #Q ((s1 . m) - (s2 . m)) <= a #Q m3
by A4, Th63;
then
a #Q ((s1 . m) - (s2 . m)) <= (m1 + 1) -Root a
by A18, Th50;
then A25:
(a #Q ((s1 . m) - (s2 . m))) - 1
<= ((m1 + 1) -Root a) - 1
by XREAL_1:9;
A26:
a #Q ((s1 . m) - (s2 . m)) > 0
by A4, Th52;
A27:
now |.((a #Q ((s1 . m) - (s2 . m))) - 1).| <= ((m1 + 1) -Root a) - 1per cases
( (s1 . m) - (s2 . m) >= 0 or (s1 . m) - (s2 . m) < 0 )
;
suppose A28:
(s1 . m) - (s2 . m) < 0
;
|.((a #Q ((s1 . m) - (s2 . m))) - 1).| <= ((m1 + 1) -Root a) - 1A29:
- ((s1 . m) - (s2 . m)) <= |.(- ((s1 . m) - (s2 . m))).|
by ABSVALUE:4;
|.((s1 . m) - (s2 . m)).| = |.(- ((s1 . m) - (s2 . m))).|
by COMPLEX1:52;
then
- ((s1 . m) - (s2 . m)) <= m3
by A17, A29, XXREAL_0:2;
then
a #Q (- ((s1 . m) - (s2 . m))) <= a #Q m3
by A4, Th63;
then
a #Q (- ((s1 . m) - (s2 . m))) <= (m1 + 1) -Root a
by A18, Th50;
then A30:
(a #Q (- ((s1 . m) - (s2 . m)))) - 1
<= ((m1 + 1) -Root a) - 1
by XREAL_1:9;
a #Q (- ((s1 . m) - (s2 . m))) >= 1
by A4, A28, Th60;
then
(a #Q (- ((s1 . m) - (s2 . m)))) - 1
>= 0
by XREAL_1:48;
then A31:
|.((a #Q (- ((s1 . m) - (s2 . m)))) - 1).| <= ((m1 + 1) -Root a) - 1
by A30, ABSVALUE:def 1;
a #Q ((s1 . m) - (s2 . m)) <= 1
by A4, A28, Th61;
then A32:
|.(a #Q ((s1 . m) - (s2 . m))).| <= 1
by A26, ABSVALUE:def 1;
|.((a #Q (- ((s1 . m) - (s2 . m)))) - 1).| >= 0
by COMPLEX1:46;
then A33:
|.(a #Q ((s1 . m) - (s2 . m))).| * |.((a #Q (- ((s1 . m) - (s2 . m)))) - 1).| <= 1
* |.((a #Q (- ((s1 . m) - (s2 . m)))) - 1).|
by A32, XREAL_1:64;
|.((a #Q ((s1 . m) - (s2 . m))) - 1).| =
|.(((a #Q ((s1 . m) - (s2 . m))) - 1) * 1).|
.=
|.(((a #Q ((s1 . m) - (s2 . m))) - 1) * ((a #Q ((s1 . m) - (s2 . m))) / (a #Q ((s1 . m) - (s2 . m))))).|
by A24, XCMPLX_1:60
.=
|.(((a #Q ((s1 . m) - (s2 . m))) * ((a #Q ((s1 . m) - (s2 . m))) - 1)) / (a #Q ((s1 . m) - (s2 . m)))).|
.=
|.((a #Q ((s1 . m) - (s2 . m))) * (((a #Q ((s1 . m) - (s2 . m))) - 1) / (a #Q ((s1 . m) - (s2 . m))))).|
.=
|.(a #Q ((s1 . m) - (s2 . m))).| * |.(((a #Q ((s1 . m) - (s2 . m))) - 1) / (a #Q ((s1 . m) - (s2 . m)))).|
by COMPLEX1:65
.=
|.(a #Q ((s1 . m) - (s2 . m))).| * |.(((a #Q ((s1 . m) - (s2 . m))) / (a #Q ((s1 . m) - (s2 . m)))) - (1 / (a #Q ((s1 . m) - (s2 . m))))).|
.=
|.(a #Q ((s1 . m) - (s2 . m))).| * |.(1 - (1 / (a #Q ((s1 . m) - (s2 . m))))).|
by A24, XCMPLX_1:60
.=
|.(a #Q ((s1 . m) - (s2 . m))).| * |.(1 - (a #Q (- ((s1 . m) - (s2 . m))))).|
by A4, Th54
.=
|.(a #Q ((s1 . m) - (s2 . m))).| * |.(- (1 - (a #Q (- ((s1 . m) - (s2 . m)))))).|
by COMPLEX1:52
.=
|.(a #Q ((s1 . m) - (s2 . m))).| * |.((a #Q (- ((s1 . m) - (s2 . m)))) - 1).|
;
hence
|.((a #Q ((s1 . m) - (s2 . m))) - 1).| <= ((m1 + 1) -Root a) - 1
by A31, A33, XXREAL_0:2;
verum end; end; end; A34:
a #Q (s2 . m) > 0
by A4, Th52;
|.(s2 . m).| <= m2
by A8, A9, XXREAL_0:2;
then
s2 . m <= m2
by A22, XXREAL_0:2;
then
a #Q (s2 . m) <= a #Q m2
by A4, Th63;
then A35:
|.(a #Q (s2 . m)).| <= a #Q m2
by A34, ABSVALUE:def 1;
|.(a #Q (s2 . m)).| >= 0
by A34, ABSVALUE:def 1;
then
|.(a #Q (s2 . m)).| * |.((a #Q ((s1 . m) - (s2 . m))) - 1).| <= (a #Q m2) * (((m1 + 1) -Root a) - 1)
by A27, A23, A35, XREAL_1:66;
then
|.((a #Q (s1 . m)) - (a #Q (s2 . m))).| <= ((a #Q m2) * (a - 1)) / (m1 + 1)
by A21, A19, XXREAL_0:2;
then
|.((a #Q (s1 . m)) - (a #Q (s2 . m))).| < c
by A15, XXREAL_0:2;
then
|.(((a #Q s1) . m) - (a #Q (s2 . m))).| < c
by Def5;
then
|.(((a #Q s1) . m) - ((a #Q s2) . m)).| < c
by Def5;
hence
|.((((a #Q s1) - (a #Q s2)) . m) - 0).| < c
by RFUNCT_2:1;
verum end;
then A36:
(a #Q s1) - (a #Q s2) is convergent
by SEQ_2:def 6;
then
lim ((a #Q s1) - (a #Q s2)) = 0
by A11, SEQ_2:def 7;
then lim (((a #Q s1) - (a #Q s2)) + (a #Q s2)) =
0 + (lim (a #Q s2))
by A36, A6, SEQ_2:6
.=
lim (a #Q s2)
;
hence
lim (a #Q s1) = lim (a #Q s2)
by A7, FUNCT_2:63; verum