let e be Real; :: thesis: ( 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
; :: thesis: 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 )
set f = seq_n^ 8;
set g = seq_a^ (1 + e),1,0 ;
set h = (seq_n^ 8) /" (seq_a^ (1 + e),1,0 );
A3:
1 + e > 0 + 0
by A1;
then reconsider g = seq_a^ (1 + e),1,0 as eventually-positive Real_Sequence ;
take
g
; :: thesis: ( 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
; :: thesis: ( Big_Oh (seq_n^ 8) c= Big_Oh g & not Big_Oh (seq_n^ 8) = Big_Oh g )
consider N being Element of NAT such that
A4:
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, Lm31;
A5:
now let p be
real number ;
:: thesis: ( p > 0 implies ex N1 being Element of NAT st
for n being Element of NAT st n >= N1 holds
abs ((((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n) - 0 ) < p )assume A6:
p > 0
;
:: thesis: ex N1 being Element of NAT st
for n being Element of NAT st n >= N1 holds
abs ((((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n) - 0 ) < preconsider p1 =
p as
Real by XREAL_0:def 1;
set N1 =
max N,
(max [/((1 / p1) to_power (1 / 8))\],2);
A7:
(
max N,
(max [/((1 / p1) to_power (1 / 8))\],2) >= N &
max N,
(max [/((1 / p1) to_power (1 / 8))\],2) >= max [/((1 / p) to_power (1 / 8))\],2 )
by XXREAL_0:25;
A8:
(
max [/((1 / p) to_power (1 / 8))\],2
>= [/((1 / p) to_power (1 / 8))\] &
max [/((1 / p) to_power (1 / 8))\],2
>= 2 )
by XXREAL_0:25;
then A9:
(
max N,
(max [/((1 / p1) to_power (1 / 8))\],2) >= [/((1 / p) to_power (1 / 8))\] &
max N,
(max [/((1 / p1) to_power (1 / 8))\],2) >= 2 )
by A7, XXREAL_0:2;
max N,
(max [/((1 / p1) to_power (1 / 8))\],2) is
Integer
then reconsider N1 =
max N,
(max [/((1 / p1) to_power (1 / 8))\],2) as
Element of
NAT by A7, INT_1:16;
take N1 =
N1;
:: thesis: for n being Element of NAT st n >= N1 holds
abs ((((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n) - 0 ) < plet n be
Element of
NAT ;
:: thesis: ( n >= N1 implies abs ((((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n) - 0 ) < p )assume A10:
n >= N1
;
:: thesis: abs ((((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n) - 0 ) < p
p " > 0
by A6;
then A11:
1
/ p > 0
;
[/((1 / p) to_power (1 / 8))\] >= (1 / p) to_power (1 / 8)
by INT_1:def 5;
then A12:
N1 >= (1 / p) to_power (1 / 8)
by A9, XXREAL_0:2;
A13:
(1 / p1) to_power (1 / 8) > 0
by A11, POWER:39;
A14:
n >= N
by A7, A10, XXREAL_0:2;
A15:
((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n = ((seq_n^ 8) . n) / (g . n)
by Lm4;
g . n = (1 + e) to_power ((1 * n) + 0 )
by Def1;
then A16:
((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n =
(n to_power 8) / ((1 + e) to_power n)
by A7, A8, A10, A15, Def3
.=
(2 to_power (8 * (log 2,n))) / ((1 + e) to_power n)
by A7, A8, A10, Lm3
.=
(2 to_power (8 * (log 2,n))) / (2 to_power (n * (log 2,(1 + e))))
by A3, Lm3
.=
2
to_power ((8 * (log 2,n)) - (n * (log 2,(1 + e))))
by POWER:34
.=
2
to_power (- ((n * (log 2,(1 + e))) - (8 * (log 2,n))))
;
n >= (1 / p) to_power (1 / 8)
by A10, A12, XXREAL_0:2;
then
n to_power 8
>= ((1 / p) to_power (1 / 8)) to_power 8
by A13, Lm6;
then
n to_power 8
>= (1 / p1) to_power ((1 / 8) * 8)
by A11, POWER:38;
then
n to_power 8
>= 1
/ p1
by POWER:30;
then
1
/ (n to_power 8) <= 1
/ (1 / p)
by A11, XREAL_1:87;
then
1
/ (n to_power 8) <= 1
/ (p " )
;
then
1
/ (n to_power 8) <= p
;
then
1
/ (2 to_power (8 * (log 2,n))) <= p
by A7, A8, A10, Lm3;
then A17:
2
to_power (- (8 * (log 2,n))) <= p
by POWER:33;
(n * (log 2,(1 + e))) - (8 * (log 2,n)) > 8
* (log 2,n)
by A4, A14;
then A18:
2
to_power ((n * (log 2,(1 + e))) - (8 * (log 2,n))) > 2
to_power (8 * (log 2,n))
by POWER:44;
2
to_power (8 * (log 2,n)) > 0
by POWER:39;
then
1
/ (2 to_power ((n * (log 2,(1 + e))) - (8 * (log 2,n)))) < 1
/ (2 to_power (8 * (log 2,n)))
by A18, XREAL_1:90;
then
2
to_power (- ((n * (log 2,(1 + e))) - (8 * (log 2,n)))) < 1
/ (2 to_power (8 * (log 2,n)))
by POWER:33;
then
((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n < 2
to_power (- (8 * (log 2,n)))
by A16, POWER:33;
then A19:
((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:39;
hence
abs ((((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) . n) - 0 ) < p
by A19, ABSVALUE:def 1;
:: thesis: verum end;
then A20:
(seq_n^ 8) /" (seq_a^ (1 + e),1,0 ) is convergent
by SEQ_2:def 6;
then
lim ((seq_n^ 8) /" (seq_a^ (1 + e),1,0 )) = 0
by A5, SEQ_2:def 7;
then
( seq_n^ 8 in Big_Oh g & not g in Big_Oh (seq_n^ 8) )
by A20, ASYMPT_0:16;
then
( seq_n^ 8 in Big_Oh g & not seq_n^ 8 in Big_Omega g )
by ASYMPT_0:19;
hence
( Big_Oh (seq_n^ 8) c= Big_Oh g & not Big_Oh (seq_n^ 8) = Big_Oh g )
by Th4; :: thesis: verum