let s1, s2 be Rational_Sequence; for a being real number 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 number ; ( 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, SEQ_2:25;
A6:
a #Q s2 is convergent
by A2, A4, Th82;
s2 is bounded
by A2, SEQ_2:27;
then consider d being real number such that
0 < d
and
A8:
for n being Element of NAT holds abs (s2 . n) < d
by SEQ_2:15;
consider m2 being Element of NAT such that
A9:
d < m2
by SEQ_4:10;
reconsider m2 = m2 as Rational ;
A10: lim (s1 - s2) =
(lim s1) - (lim s2)
by A1, A2, SEQ_2:26
.=
0
by A3
;
A11:
now A12:
a #Q m2 >= 0
by A4, Th63;
let c be
real number ;
( c > 0 implies ex n being Element of NAT st
for m being Element of NAT st m >= n holds
abs ((((a #Q s1) - (a #Q s2)) . m) - 0 ) < c )assume A13:
c > 0
;
ex n being Element of NAT st
for m being Element of NAT st m >= n holds
abs ((((a #Q s1) - (a #Q s2)) . m) - 0 ) < cconsider m1 being
Element of
NAT such that A14:
((a #Q m2) * (a - 1)) / c < m1
by SEQ_4:10;
m1 + 1
>= m1
by XREAL_1:31;
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_1:70;
then
(a #Q m2) * (a - 1) < c * (m1 + 1)
by A13, XCMPLX_1:88;
then
((a #Q m2) * (a - 1)) / (m1 + 1) < ((m1 + 1) * c) / (m1 + 1)
by XREAL_1:76;
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_1:88;
consider n being
Element of
NAT such that A16:
for
m being
Element of
NAT st
n <= m holds
abs (((s1 - s2) . m) - 0 ) < (m1 + 1) "
by A5, A10, SEQ_2:def 7;
take n =
n;
for m being Element of NAT st m >= n holds
abs ((((a #Q s1) - (a #Q s2)) . m) - 0 ) < clet m be
Element of
NAT ;
( m >= n implies abs ((((a #Q s1) - (a #Q s2)) . m) - 0 ) < c )assume
m >= n
;
abs ((((a #Q s1) - (a #Q s2)) . m) - 0 ) < cthen
abs (((s1 - s2) . m) - 0 ) < (m1 + 1) "
by A16;
then A17:
abs ((s1 . m) - (s2 . m)) <= (m1 + 1) "
by RFUNCT_2:6;
A18:
m1 + 1
>= 0 + 1
by NAT_1:13;
then
((m1 + 1) -Root a) - 1
<= (a - 1) / (m1 + 1)
by A4, Th40;
then A19:
(a #Q m2) * (((m1 + 1) -Root a) - 1) <= (a #Q m2) * ((a - 1) / (m1 + 1))
by A12, XREAL_1:66;
A20:
a #Q (s2 . m) <> 0
by A4, Th63;
A21:
abs ((a #Q (s1 . m)) - (a #Q (s2 . m))) =
abs (((a #Q (s1 . m)) - (a #Q (s2 . m))) * 1)
.=
abs (((a #Q (s1 . m)) - (a #Q (s2 . m))) * ((a #Q (s2 . m)) / (a #Q (s2 . m))))
by A20, XCMPLX_1:60
.=
abs (((a #Q (s2 . m)) * ((a #Q (s1 . m)) - (a #Q (s2 . m)))) / (a #Q (s2 . m)))
.=
abs ((a #Q (s2 . m)) * (((a #Q (s1 . m)) - (a #Q (s2 . m))) / (a #Q (s2 . m))))
.=
(abs (a #Q (s2 . m))) * (abs (((a #Q (s1 . m)) - (a #Q (s2 . m))) / (a #Q (s2 . m))))
by COMPLEX1:151
.=
(abs (a #Q (s2 . m))) * (abs (((a #Q (s1 . m)) / (a #Q (s2 . m))) - ((a #Q (s2 . m)) / (a #Q (s2 . m)))))
.=
(abs (a #Q (s2 . m))) * (abs (((a #Q (s1 . m)) / (a #Q (s2 . m))) - 1))
by A20, XCMPLX_1:60
.=
(abs (a #Q (s2 . m))) * (abs ((a #Q ((s1 . m) - (s2 . m))) - 1))
by A4, Th66
;
A22:
s2 . m <= abs (s2 . m)
by ABSVALUE:11;
reconsider m3 =
(m1 + 1) " as
Rational ;
A23:
abs ((a #Q ((s1 . m) - (s2 . m))) - 1) >= 0
by COMPLEX1:132;
A24:
a #Q ((s1 . m) - (s2 . m)) <> 0
by A4, Th63;
(s1 . m) - (s2 . m) <= abs ((s1 . m) - (s2 . m))
by ABSVALUE:11;
then
(s1 . m) - (s2 . m) <= (m1 + 1) "
by A17, XXREAL_0:2;
then
a #Q ((s1 . m) - (s2 . m)) <= a #Q m3
by A4, Th74;
then
a #Q ((s1 . m) - (s2 . m)) <= (m1 + 1) -Root a
by A18, Th61;
then A25:
(a #Q ((s1 . m) - (s2 . m))) - 1
<= ((m1 + 1) -Root a) - 1
by XREAL_1:11;
A26:
a #Q ((s1 . m) - (s2 . m)) > 0
by A4, Th63;
A27:
now per cases
( (s1 . m) - (s2 . m) >= 0 or (s1 . m) - (s2 . m) < 0 )
;
suppose A28:
(s1 . m) - (s2 . m) < 0
;
abs ((a #Q ((s1 . m) - (s2 . m))) - 1) <= ((m1 + 1) -Root a) - 1A29:
- ((s1 . m) - (s2 . m)) <= abs (- ((s1 . m) - (s2 . m)))
by ABSVALUE:11;
abs ((s1 . m) - (s2 . m)) = abs (- ((s1 . m) - (s2 . m)))
by COMPLEX1:138;
then
- ((s1 . m) - (s2 . m)) <= m3
by A17, A29, XXREAL_0:2;
then
a #Q (- ((s1 . m) - (s2 . m))) <= a #Q m3
by A4, Th74;
then
a #Q (- ((s1 . m) - (s2 . m))) <= (m1 + 1) -Root a
by A18, Th61;
then A30:
(a #Q (- ((s1 . m) - (s2 . m)))) - 1
<= ((m1 + 1) -Root a) - 1
by XREAL_1:11;
a #Q (- ((s1 . m) - (s2 . m))) >= 1
by A4, A28, Th71;
then
(a #Q (- ((s1 . m) - (s2 . m)))) - 1
>= 0
by XREAL_1:50;
then A31:
abs ((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, Th72;
then A32:
abs (a #Q ((s1 . m) - (s2 . m))) <= 1
by A26, ABSVALUE:def 1;
abs ((a #Q (- ((s1 . m) - (s2 . m)))) - 1) >= 0
by COMPLEX1:132;
then A33:
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs ((a #Q (- ((s1 . m) - (s2 . m)))) - 1)) <= 1
* (abs ((a #Q (- ((s1 . m) - (s2 . m)))) - 1))
by A32, XREAL_1:66;
abs ((a #Q ((s1 . m) - (s2 . m))) - 1) =
abs (((a #Q ((s1 . m) - (s2 . m))) - 1) * 1)
.=
abs (((a #Q ((s1 . m) - (s2 . m))) - 1) * ((a #Q ((s1 . m) - (s2 . m))) / (a #Q ((s1 . m) - (s2 . m)))))
by A24, XCMPLX_1:60
.=
abs (((a #Q ((s1 . m) - (s2 . m))) * ((a #Q ((s1 . m) - (s2 . m))) - 1)) / (a #Q ((s1 . m) - (s2 . m))))
.=
abs ((a #Q ((s1 . m) - (s2 . m))) * (((a #Q ((s1 . m) - (s2 . m))) - 1) / (a #Q ((s1 . m) - (s2 . m)))))
.=
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs (((a #Q ((s1 . m) - (s2 . m))) - 1) / (a #Q ((s1 . m) - (s2 . m)))))
by COMPLEX1:151
.=
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs (((a #Q ((s1 . m) - (s2 . m))) / (a #Q ((s1 . m) - (s2 . m)))) - (1 / (a #Q ((s1 . m) - (s2 . m))))))
.=
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs (1 - (1 / (a #Q ((s1 . m) - (s2 . m))))))
by A24, XCMPLX_1:60
.=
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs (1 - (a #Q (- ((s1 . m) - (s2 . m))))))
by A4, Th65
.=
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs (- (1 - (a #Q (- ((s1 . m) - (s2 . m)))))))
by COMPLEX1:138
.=
(abs (a #Q ((s1 . m) - (s2 . m)))) * (abs ((a #Q (- ((s1 . m) - (s2 . m)))) - 1))
;
hence
abs ((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, Th63;
abs (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, Th74;
then A35:
abs (a #Q (s2 . m)) <= a #Q m2
by A34, ABSVALUE:def 1;
abs (a #Q (s2 . m)) >= 0
by A34, ABSVALUE:def 1;
then
(abs (a #Q (s2 . m))) * (abs ((a #Q ((s1 . m) - (s2 . m))) - 1)) <= (a #Q m2) * (((m1 + 1) -Root a) - 1)
by A27, A23, A35, XREAL_1:68;
then
abs ((a #Q (s1 . m)) - (a #Q (s2 . m))) <= ((a #Q m2) * (a - 1)) / (m1 + 1)
by A21, A19, XXREAL_0:2;
then
abs ((a #Q (s1 . m)) - (a #Q (s2 . m))) < c
by A15, XXREAL_0:2;
then
abs (((a #Q s1) . m) - (a #Q (s2 . m))) < c
by Def7;
then
abs (((a #Q s1) . m) - ((a #Q s2) . m)) < c
by Def7;
hence
abs ((((a #Q s1) - (a #Q s2)) . m) - 0 ) < c
by RFUNCT_2:6;
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_2:20
.=
lim (a #Q s2)
;
hence
lim (a #Q s1) = lim (a #Q s2)
by A7, FUNCT_2:113; verum