set f = seq_n^ 8;
let e be Real; ( 0 < e & e < 1 implies ex s being eventually-positive Real_Sequence st
( s = seq_a^ ((1 + e),1,0) & Big_Oh (seq_n^ 8) c= Big_Oh s & not Big_Oh (seq_n^ 8) = Big_Oh s ) )
assume that
A1:
0 < e
and
A2:
e < 1
; ex s being eventually-positive Real_Sequence st
( s = seq_a^ ((1 + e),1,0) & Big_Oh (seq_n^ 8) c= Big_Oh s & not Big_Oh (seq_n^ 8) = Big_Oh s )
consider N being Element of NAT such that
A3:
for n being Element of NAT st n >= N holds
(n * (log (2,(1 + e)))) - (8 * (log (2,n))) > 8 * (log (2,n))
by A1, A2, Lm25;
set g = seq_a^ ((1 + e),1,0);
set h = (seq_n^ 8) /" (seq_a^ ((1 + e),1,0));
reconsider g = seq_a^ ((1 + e),1,0) as eventually-positive Real_Sequence by A1;
take
g
; ( g = seq_a^ ((1 + e),1,0) & Big_Oh (seq_n^ 8) c= Big_Oh g & not Big_Oh (seq_n^ 8) = Big_Oh g )
thus
g = seq_a^ ((1 + e),1,0)
; ( Big_Oh (seq_n^ 8) c= Big_Oh g & not Big_Oh (seq_n^ 8) = Big_Oh g )
A4:
now for p being Real st p > 0 holds
ex N1 being Nat st
for n being Nat st n >= N1 holds
|.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < plet p be
Real;
( p > 0 implies ex N1 being Nat st
for n being Nat st n >= N1 holds
|.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < p )assume A5:
p > 0
;
ex N1 being Nat st
for n being Nat st n >= N1 holds
|.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < preconsider p1 =
p as
Real ;
A6:
(1 / p1) to_power (1 / 8) > 0
by A5, POWER:34;
set N1 =
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2)));
A7:
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2)))
>= N
by XXREAL_0:25;
A8:
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2))) is
Integer
A9:
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2)))
>= max (
[/((1 / p) to_power (1 / 8))\],2)
by XXREAL_0:25;
max (
[/((1 / p) to_power (1 / 8))\],2)
>= [/((1 / p) to_power (1 / 8))\]
by XXREAL_0:25;
then A10:
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2)))
>= [/((1 / p) to_power (1 / 8))\]
by A9, XXREAL_0:2;
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2)))
in NAT
by A7, A8, INT_1:3;
then reconsider N1 =
max (
N,
(max ([/((1 / p1) to_power (1 / 8))\],2))) as
Nat ;
take N1 =
N1;
for n being Nat st n >= N1 holds
|.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < plet n be
Nat;
( n >= N1 implies |.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < p )A11:
n in NAT
by ORDINAL1:def 12;
assume A12:
n >= N1
;
|.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < pthen
n >= N
by A7, XXREAL_0:2;
then
(n * (log (2,(1 + e)))) - (8 * (log (2,n))) > 8
* (log (2,n))
by A3, A11;
then A13:
2
to_power ((n * (log (2,(1 + e)))) - (8 * (log (2,n)))) > 2
to_power (8 * (log (2,n)))
by POWER:39;
A14:
max (
[/((1 / p) to_power (1 / 8))\],2)
>= 2
by XXREAL_0:25;
A15:
g . n = (1 + e) to_power ((1 * n) + 0)
by Def1;
((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n = ((seq_n^ 8) . n) / (g . n)
by Lm4;
then A16:
((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n =
(n to_power 8) / ((1 + e) to_power n)
by A9, A14, A12, A15, Def3
.=
(2 to_power (8 * (log (2,n)))) / ((1 + e) to_power n)
by A9, A14, A12, Lm3
.=
(2 to_power (8 * (log (2,n)))) / (2 to_power (n * (log (2,(1 + e)))))
by A1, Lm3
.=
2
to_power ((8 * (log (2,n))) - (n * (log (2,(1 + e)))))
by POWER:29
.=
2
to_power (- ((n * (log (2,(1 + e)))) - (8 * (log (2,n)))))
;
[/((1 / p) to_power (1 / 8))\] >= (1 / p) to_power (1 / 8)
by INT_1:def 7;
then
N1 >= (1 / p) to_power (1 / 8)
by A10, XXREAL_0:2;
then
n >= (1 / p) to_power (1 / 8)
by A12, XXREAL_0:2;
then
n to_power 8
>= ((1 / p) to_power (1 / 8)) to_power 8
by A6, Lm6;
then
n to_power 8
>= (1 / p1) to_power ((1 / 8) * 8)
by A5, POWER:33;
then
n to_power 8
>= 1
/ p1
by POWER:25;
then
1
/ (n to_power 8) <= 1
/ (p ")
by A5, XREAL_1:85;
then
1
/ (2 to_power (8 * (log (2,n)))) <= p
by A9, A14, A12, Lm3;
then A17:
2
to_power (- (8 * (log (2,n)))) <= p
by POWER:28;
2
to_power (8 * (log (2,n))) > 0
by POWER:34;
then
1
/ (2 to_power ((n * (log (2,(1 + e)))) - (8 * (log (2,n))))) < 1
/ (2 to_power (8 * (log (2,n))))
by A13, XREAL_1:88;
then
2
to_power (- ((n * (log (2,(1 + e)))) - (8 * (log (2,n))))) < 1
/ (2 to_power (8 * (log (2,n))))
by POWER:28;
then
((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n < 2
to_power (- (8 * (log (2,n))))
by A16, POWER:28;
then A18:
((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n < p
by A17, XXREAL_0:2;
((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n > 0
by A16, POWER:34;
hence
|.((((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) . n) - 0).| < p
by A18, ABSVALUE:def 1;
verum end;
then A19:
(seq_n^ 8) /" (seq_a^ ((1 + e),1,0)) is convergent
by SEQ_2:def 6;
then A20:
lim ((seq_n^ 8) /" (seq_a^ ((1 + e),1,0))) = 0
by A4, SEQ_2:def 7;
then
not g in Big_Oh (seq_n^ 8)
by A19, ASYMPT_0:16;
then A21:
not seq_n^ 8 in Big_Omega g
by ASYMPT_0:19;
seq_n^ 8 in Big_Oh g
by A19, A20, ASYMPT_0:16;
hence
( Big_Oh (seq_n^ 8) c= Big_Oh g & not Big_Oh (seq_n^ 8) = Big_Oh g )
by A21, Th4; verum