let f be eventually-nonnegative Real_Sequence; for t being eventually-nonnegative eventually-nondecreasing Real_Sequence
for b being Element of NAT st f is smooth & b >= 2 & t in Big_Theta f,{ (b |^ n) where n is Element of NAT : verum } holds
t in Big_Theta f
let t be eventually-nonnegative eventually-nondecreasing Real_Sequence; for b being Element of NAT st f is smooth & b >= 2 & t in Big_Theta f,{ (b |^ n) where n is Element of NAT : verum } holds
t in Big_Theta f
let b be Element of NAT ; ( f is smooth & b >= 2 & t in Big_Theta f,{ (b |^ n) where n is Element of NAT : verum } implies t in Big_Theta f )
assume that
A1:
( f is smooth & b >= 2 )
and
A2:
t in Big_Theta f,{ (b |^ n) where n is Element of NAT : verum }
; t in Big_Theta f
set X = { (b |^ n) where n is Element of NAT : verum } ;
A3:
t in (Big_Oh f,{ (b |^ n) where n is Element of NAT : verum } ) /\ (Big_Omega f,{ (b |^ n) where n is Element of NAT : verum } )
by A2, Th36;
then
t in Big_Omega f,{ (b |^ n) where n is Element of NAT : verum }
by XBOOLE_0:def 4;
then A4:
t in Big_Omega f
by A1, Th39;
t in Big_Oh f,{ (b |^ n) where n is Element of NAT : verum }
by A3, XBOOLE_0:def 4;
then
t in Big_Oh f
by A1, Th38;
hence
t in Big_Theta f
by A4, XBOOLE_0:def 4; verum