:: Asymptotic notation. Part I: Theory
:: by Richard Krueger , Piotr Rudnicki and Paul Shelley
::
:: Received November 4, 1999
:: Copyright (c) 1999 Association of Mizar Users

scheme :: ASYMPT_0:sch 1
FinSegRng1{ F₁() -> Nat, F₂() -> Nat, F₃() -> non empty set , F₄( set ) -> Element of F₃() } :

{ F₄(i) where i is Element of NAT : ( F₁() <= i & i <= F₂() ) } is non empty finite Subset of F₃()

provided

A1: F₁() <= F₂()

proof end;

scheme :: ASYMPT_0:sch 2
FinImInit1{ F₁() -> Nat, F₂() -> non empty set , F₃( set ) -> Element of F₂() } :

{ F₃(n) where n is Element of NAT : n <= F₁() } is non empty finite Subset of F₂()

proof end;

scheme :: ASYMPT_0:sch 3
FinImInit2{ F₁() -> Nat, F₂() -> non empty set , F₃( set ) -> Element of F₂() } :

{ F₃(n) where n is Element of NAT : n < F₁() } is non empty finite Subset of F₂()

provided

A1: F₁() > 0

proof end;

definition

let c be real number ;
canceled;
canceled;
attr c is logbase means :Def3: :: ASYMPT_0:def 3
( c > 0 & c <> 1 );

end;

:: deftheorem ASYMPT_0:def 1 :

canceled;

:: deftheorem ASYMPT_0:def 2 :

canceled;

:: deftheorem Def3 defines logbase ASYMPT_0:def 3 :

for c being real number holds
( c is logbase iff ( c > 0 & c <> 1 ) );

registration

cluster positive Element of REAL ;
existence
ex b₁ being Real st b₁ is positive

proof end;

cluster negative Element of REAL ;
existence
ex b₁ being Real st b₁ is negative

proof end;

cluster logbase Element of REAL ;
existence
ex b₁ being Real st b₁ is logbase

proof end;

cluster non negative Element of REAL ;
existence
not for b₁ being Real holds b₁ is negative by XXREAL_0:def 7;
cluster non positive Element of REAL ;
existence
not for b₁ being Real holds b₁ is positive by XXREAL_0:def 6;
cluster non logbase Element of REAL ;
existence
not for b₁ being Real holds b₁ is logbase

proof end;

end;

definition

let f be Real_Sequence;
attr f is eventually-nonnegative means :Def4: :: ASYMPT_0:def 4
ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n >= 0 ;
attr f is positive means :Def5: :: ASYMPT_0:def 5
for n being Element of NAT holds f . n > 0 ;
attr f is eventually-positive means :Def6: :: ASYMPT_0:def 6
ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n > 0 ;
attr f is eventually-nonzero means :Def7: :: ASYMPT_0:def 7
ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n <> 0 ;
attr f is eventually-nondecreasing means :Def8: :: ASYMPT_0:def 8
ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n <= f . (n + 1);

end;

:: deftheorem Def4 defines eventually-nonnegative ASYMPT_0:def 4 :

for f being Real_Sequence holds
( f is eventually-nonnegative iff ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n >= 0 );

:: deftheorem Def5 defines positive ASYMPT_0:def 5 :

for f being Real_Sequence holds
( f is positive iff for n being Element of NAT holds f . n > 0 );

:: deftheorem Def6 defines eventually-positive ASYMPT_0:def 6 :

for f being Real_Sequence holds
( f is eventually-positive iff ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n > 0 );

:: deftheorem Def7 defines eventually-nonzero ASYMPT_0:def 7 :

for f being Real_Sequence holds
( f is eventually-nonzero iff ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n <> 0 );

:: deftheorem Def8 defines eventually-nondecreasing ASYMPT_0:def 8 :

for f being Real_Sequence holds
( f is eventually-nondecreasing iff ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n <= f . (n + 1) );

registration

cluster eventually-nonnegative positive eventually-positive eventually-nonzero eventually-nondecreasing M4( NAT , REAL );
existence
ex b₁ being Real_Sequence st
( b₁ is eventually-nonnegative & b₁ is eventually-nonzero & b₁ is positive & b₁ is eventually-positive & b₁ is eventually-nondecreasing )

proof end;

end;

definition

let c, d be Real;
:: original: min
redefine func min c,d -> Real;
coherence
min c,d is Real by XREAL_0:def 1;
:: original: max
redefine func max c,d -> Real;
coherence
max c,d is Real by XREAL_0:def 1;

end;

definition

let N, M be Element of NAT ;
:: original: min
redefine func min N,M -> Element of NAT ;
coherence
min N,M is Element of NAT by XXREAL_0:15;
:: original: max
redefine func max N,M -> Element of NAT ;
coherence
max N,M is Element of NAT by XXREAL_0:16;

end;

registration

cluster positive -> eventually-positive M4( NAT , REAL );
coherence
for b₁ being Real_Sequence st b₁ is positive holds
b₁ is eventually-positive

proof end;

cluster eventually-positive -> eventually-nonnegative eventually-nonzero M4( NAT , REAL );
coherence
for b₁ being Real_Sequence st b₁ is eventually-positive holds
( b₁ is eventually-nonnegative & b₁ is eventually-nonzero )

proof end;

cluster eventually-nonnegative eventually-nonzero -> eventually-positive M4( NAT , REAL );
coherence
for b₁ being Real_Sequence st b₁ is eventually-nonnegative & b₁ is eventually-nonzero holds
b₁ is eventually-positive

proof end;

end;

definition

let f, g be eventually-nonnegative Real_Sequence;
:: original: +
redefine func f + g -> eventually-nonnegative Real_Sequence;
coherence
f + g is eventually-nonnegative Real_Sequence

proof end;

end;

definition

let f be eventually-nonnegative Real_Sequence;
let c be positive Real;
canceled;
:: original: (#)
redefine func c (#) f -> eventually-nonnegative Real_Sequence;
coherence
c (#) f is eventually-nonnegative Real_Sequence

proof end;

end;

:: deftheorem ASYMPT_0:def 9 :

canceled;

definition

let f be eventually-nonnegative Real_Sequence;
let c be non negative Real;
:: original: +
redefine func c + f -> eventually-nonnegative Real_Sequence;
coherence
c + f is eventually-nonnegative Real_Sequence

proof end;

end;

definition

let f be eventually-nonnegative Real_Sequence;
let c be positive Real;
:: original: +
redefine func c + f -> eventually-positive Real_Sequence;
coherence
c + f is eventually-positive Real_Sequence

proof end;

end;

definition

let f, g be Real_Sequence;
func max f,g -> Real_Sequence means :Def10: :: ASYMPT_0:def 10
for n being Element of NAT holds it . n = max (f . n),(g . n);
existence
ex b₁ being Real_Sequence st
for n being Element of NAT holds b₁ . n = max (f . n),(g . n)

proof end;

uniqueness
for b₁, b₂ being Real_Sequence st ( for n being Element of NAT holds b₁ . n = max (f . n),(g . n) ) & ( for n being Element of NAT holds b₂ . n = max (f . n),(g . n) ) holds
b₁ = b₂

proof end;

commutativity
for b₁, f, g being Real_Sequence st ( for n being Element of NAT holds b₁ . n = max (f . n),(g . n) ) holds
for n being Element of NAT holds b₁ . n = max (g . n),(f . n) ;

end;

:: deftheorem Def10 defines max ASYMPT_0:def 10 :

for f, g, b₃ being Real_Sequence holds
( b₃ = max f,g iff for n being Element of NAT holds b₃ . n = max (f . n),(g . n) );

registration

let f be Real_Sequence;
let g be eventually-nonnegative Real_Sequence;
cluster max f,g -> eventually-nonnegative ;
coherence
max f,g is eventually-nonnegative

proof end;

end;

registration

let f be Real_Sequence;
let g be eventually-positive Real_Sequence;
cluster max f,g -> eventually-positive ;
coherence
max f,g is eventually-positive

proof end;

end;

definition

let f, g be Real_Sequence;
pred g majorizes f means :Def11: :: ASYMPT_0:def 11
ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n <= g . n;

end;

:: deftheorem Def11 defines majorizes ASYMPT_0:def 11 :

for f, g being Real_Sequence holds
( g majorizes f iff ex N being Element of NAT st
for n being Element of NAT st n >= N holds
f . n <= g . n );

Lm1: for f, g being Real_Sequence
for n being Element of NAT holds (f /" g) . n = (f . n) / (g . n)

proof end;

theorem Th1: :: ASYMPT_0:1

for f being Real_Sequence
for N being Element of NAT st ( for n being Element of NAT st n >= N holds
f . n <= f . (n + 1) ) holds
for n, m being Element of NAT st N <= n & n <= m holds
f . n <= f . m

proof end;

theorem Th2: :: ASYMPT_0:2

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) <> 0 holds
( g /" f is convergent & lim (g /" f) = (lim (f /" g)) " )

proof end;

theorem Th3: :: ASYMPT_0:3

for f being eventually-nonnegative Real_Sequence st f is convergent holds
0 <= lim f

proof end;

theorem Th4: :: ASYMPT_0:4

for f, g being Real_Sequence st f is convergent & g is convergent & g majorizes f holds
lim f <= lim g

proof end;

theorem Th5: :: ASYMPT_0:5

for f being Real_Sequence
for g being eventually-nonzero Real_Sequence st f /" g is divergent_to+infty holds
( g /" f is convergent & lim (g /" f) = 0 )

proof end;

definition

let f be eventually-nonnegative Real_Sequence;
func Big_Oh f -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 12
{ t where t is Element of Funcs NAT ,REAL : ex c being Real ex N being Element of NAT st
( c > 0 & ( for n being Element of NAT st n >= N holds
( t . n <= c * (f . n) & t . n >= 0 ) ) ) } ;
coherence
{ t where t is Element of Funcs NAT ,REAL : ex c being Real ex N being Element of NAT st
( c > 0 & ( for n being Element of NAT st n >= N holds
( t . n <= c * (f . n) & t . n >= 0 ) ) ) } is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines Big_Oh ASYMPT_0:def 12 :

for f being eventually-nonnegative Real_Sequence holds Big_Oh f = { t where t is Element of Funcs NAT ,REAL : ex c being Real ex N being Element of NAT st
( c > 0 & ( for n being Element of NAT st n >= N holds
( t . n <= c * (f . n) & t . n >= 0 ) ) ) } ;

theorem Th6: :: ASYMPT_0:6

for x being set
for f being eventually-nonnegative Real_Sequence st x in Big_Oh f holds
x is eventually-nonnegative Real_Sequence

proof end;

theorem :: ASYMPT_0:7

for f being positive Real_Sequence
for t being eventually-nonnegative Real_Sequence holds
( t in Big_Oh f iff ex c being Real st
( c > 0 & ( for n being Element of NAT holds t . n <= c * (f . n) ) ) )

proof end;

theorem :: ASYMPT_0:8

for f being eventually-positive Real_Sequence
for t being eventually-nonnegative Real_Sequence
for N being Element of NAT st t in Big_Oh f & ( for n being Element of NAT st n >= N holds
f . n > 0 ) holds
ex c being Real st
( c > 0 & ( for n being Element of NAT st n >= N holds
t . n <= c * (f . n) ) )

proof end;

theorem :: ASYMPT_0:9

for f, g being eventually-nonnegative Real_Sequence holds Big_Oh (f + g) = Big_Oh (max f,g)

proof end;

theorem Th10: :: ASYMPT_0:10

for f being eventually-nonnegative Real_Sequence holds f in Big_Oh f

proof end;

theorem Th11: :: ASYMPT_0:11

for f, g being eventually-nonnegative Real_Sequence st f in Big_Oh g holds
Big_Oh f c= Big_Oh g

proof end;

theorem Th12: :: ASYMPT_0:12

for f, g, h being eventually-nonnegative Real_Sequence st f in Big_Oh g & g in Big_Oh h holds
f in Big_Oh h

proof end;

Lm2: for f, g being eventually-nonnegative Real_Sequence holds
( ( f in Big_Oh g & g in Big_Oh f ) iff Big_Oh f = Big_Oh g )

proof end;

theorem :: ASYMPT_0:13

for f being eventually-nonnegative Real_Sequence
for c being positive Real holds Big_Oh f = Big_Oh (c (#) f)

proof end;

theorem :: ASYMPT_0:14

for c being non negative Real
for x, f being eventually-nonnegative Real_Sequence st x in Big_Oh f holds
x in Big_Oh (c + f)

proof end;

Lm3: for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) > 0 holds
f in Big_Oh g

proof end;

theorem Th15: :: ASYMPT_0:15

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) > 0 holds
Big_Oh f = Big_Oh g

proof end;

theorem Th16: :: ASYMPT_0:16

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) = 0 holds
( f in Big_Oh g & not g in Big_Oh f )

proof end;

theorem Th17: :: ASYMPT_0:17

for f, g being eventually-positive Real_Sequence st f /" g is divergent_to+infty holds
( not f in Big_Oh g & g in Big_Oh f )

proof end;

definition

let f be eventually-nonnegative Real_Sequence;
func Big_Omega f -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 13
{ t where t is Element of Funcs NAT ,REAL : ex d being Real ex N being Element of NAT st
( d > 0 & ( for n being Element of NAT st n >= N holds
( t . n >= d * (f . n) & t . n >= 0 ) ) ) } ;
coherence
{ t where t is Element of Funcs NAT ,REAL : ex d being Real ex N being Element of NAT st
( d > 0 & ( for n being Element of NAT st n >= N holds
( t . n >= d * (f . n) & t . n >= 0 ) ) ) } is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines Big_Omega ASYMPT_0:def 13 :

for f being eventually-nonnegative Real_Sequence holds Big_Omega f = { t where t is Element of Funcs NAT ,REAL : ex d being Real ex N being Element of NAT st
( d > 0 & ( for n being Element of NAT st n >= N holds
( t . n >= d * (f . n) & t . n >= 0 ) ) ) } ;

theorem :: ASYMPT_0:18

for x being set
for f being eventually-nonnegative Real_Sequence st x in Big_Omega f holds
x is eventually-nonnegative Real_Sequence

proof end;

theorem Th19: :: ASYMPT_0:19

for f, g being eventually-nonnegative Real_Sequence holds
( f in Big_Omega g iff g in Big_Oh f )

proof end;

theorem Th20: :: ASYMPT_0:20

for f being eventually-nonnegative Real_Sequence holds f in Big_Omega f

proof end;

theorem Th21: :: ASYMPT_0:21

for f, g, h being eventually-nonnegative Real_Sequence st f in Big_Omega g & g in Big_Omega h holds
f in Big_Omega h

proof end;

theorem :: ASYMPT_0:22

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) > 0 holds
Big_Omega f = Big_Omega g

proof end;

theorem Th23: :: ASYMPT_0:23

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) = 0 holds
( g in Big_Omega f & not f in Big_Omega g )

proof end;

theorem :: ASYMPT_0:24

for f, g being eventually-positive Real_Sequence st f /" g is divergent_to+infty holds
( not g in Big_Omega f & f in Big_Omega g )

proof end;

theorem :: ASYMPT_0:25

for f, t being positive Real_Sequence holds
( t in Big_Omega f iff ex d being Real st
( d > 0 & ( for n being Element of NAT holds d * (f . n) <= t . n ) ) )

proof end;

theorem :: ASYMPT_0:26

for f, g being eventually-nonnegative Real_Sequence holds Big_Omega (f + g) = Big_Omega (max f,g)

proof end;

definition

let f be eventually-nonnegative Real_Sequence;
func Big_Theta f -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 14
(Big_Oh f) /\ (Big_Omega f);
coherence
(Big_Oh f) /\ (Big_Omega f) is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines Big_Theta ASYMPT_0:def 14 :

for f being eventually-nonnegative Real_Sequence holds Big_Theta f = (Big_Oh f) /\ (Big_Omega f);

theorem Th27: :: ASYMPT_0:27

for f being eventually-nonnegative Real_Sequence holds Big_Theta f = { t where t is Element of Funcs NAT ,REAL : ex c, d being Real ex N being Element of NAT st
( c > 0 & d > 0 & ( for n being Element of NAT st n >= N holds
( d * (f . n) <= t . n & t . n <= c * (f . n) ) ) ) }

proof end;

theorem :: ASYMPT_0:28

for f being eventually-nonnegative Real_Sequence holds f in Big_Theta f

proof end;

theorem :: ASYMPT_0:29

for f, g being eventually-nonnegative Real_Sequence st f in Big_Theta g holds
g in Big_Theta f

proof end;

theorem :: ASYMPT_0:30

for f, g, h being eventually-nonnegative Real_Sequence st f in Big_Theta g & g in Big_Theta h holds
f in Big_Theta h

proof end;

theorem :: ASYMPT_0:31

for f, t being positive Real_Sequence holds
( t in Big_Theta f iff ex c, d being Real st
( c > 0 & d > 0 & ( for n being Element of NAT holds
( d * (f . n) <= t . n & t . n <= c * (f . n) ) ) ) )

proof end;

theorem :: ASYMPT_0:32

for f, g being eventually-nonnegative Real_Sequence holds Big_Theta (f + g) = Big_Theta (max f,g)

proof end;

theorem :: ASYMPT_0:33

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) > 0 holds
f in Big_Theta g

proof end;

theorem :: ASYMPT_0:34

for f, g being eventually-positive Real_Sequence st f /" g is convergent & lim (f /" g) = 0 holds
( f in Big_Oh g & not f in Big_Theta g )

proof end;

theorem :: ASYMPT_0:35

for f, g being eventually-positive Real_Sequence st f /" g is divergent_to+infty holds
( f in Big_Omega g & not f in Big_Theta g )

proof end;

definition

let f be eventually-nonnegative Real_Sequence;
let X be set ;
func Big_Oh f,X -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 15
{ t where t is Element of Funcs NAT ,REAL : ex c being Real ex N being Element of NAT st
( c > 0 & ( for n being Element of NAT st n >= N & n in X holds
( t . n <= c * (f . n) & t . n >= 0 ) ) ) } ;
coherence
{ t where t is Element of Funcs NAT ,REAL : ex c being Real ex N being Element of NAT st
( c > 0 & ( for n being Element of NAT st n >= N & n in X holds
( t . n <= c * (f . n) & t . n >= 0 ) ) ) } is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines Big_Oh ASYMPT_0:def 15 :

for f being eventually-nonnegative Real_Sequence
for X being set holds Big_Oh f,X = { t where t is Element of Funcs NAT ,REAL : ex c being Real ex N being Element of NAT st
( c > 0 & ( for n being Element of NAT st n >= N & n in X holds
( t . n <= c * (f . n) & t . n >= 0 ) ) ) } ;

definition

let f be eventually-nonnegative Real_Sequence;
let X be set ;
func Big_Omega f,X -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 16
{ t where t is Element of Funcs NAT ,REAL : ex d being Real ex N being Element of NAT st
( d > 0 & ( for n being Element of NAT st n >= N & n in X holds
( t . n >= d * (f . n) & t . n >= 0 ) ) ) } ;
coherence
{ t where t is Element of Funcs NAT ,REAL : ex d being Real ex N being Element of NAT st
( d > 0 & ( for n being Element of NAT st n >= N & n in X holds
( t . n >= d * (f . n) & t . n >= 0 ) ) ) } is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines Big_Omega ASYMPT_0:def 16 :

for f being eventually-nonnegative Real_Sequence
for X being set holds Big_Omega f,X = { t where t is Element of Funcs NAT ,REAL : ex d being Real ex N being Element of NAT st
( d > 0 & ( for n being Element of NAT st n >= N & n in X holds
( t . n >= d * (f . n) & t . n >= 0 ) ) ) } ;

definition

let f be eventually-nonnegative Real_Sequence;
let X be set ;
func Big_Theta f,X -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 17
{ t where t is Element of Funcs NAT ,REAL : ex c, d being Real ex N being Element of NAT st
( c > 0 & d > 0 & ( for n being Element of NAT st n >= N & n in X holds
( d * (f . n) <= t . n & t . n <= c * (f . n) ) ) ) } ;
coherence
{ t where t is Element of Funcs NAT ,REAL : ex c, d being Real ex N being Element of NAT st
( c > 0 & d > 0 & ( for n being Element of NAT st n >= N & n in X holds
( d * (f . n) <= t . n & t . n <= c * (f . n) ) ) ) } is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines Big_Theta ASYMPT_0:def 17 :

for f being eventually-nonnegative Real_Sequence
for X being set holds Big_Theta f,X = { t where t is Element of Funcs NAT ,REAL : ex c, d being Real ex N being Element of NAT st
( c > 0 & d > 0 & ( for n being Element of NAT st n >= N & n in X holds
( d * (f . n) <= t . n & t . n <= c * (f . n) ) ) ) } ;

theorem Th36: :: ASYMPT_0:36

for f being eventually-nonnegative Real_Sequence
for X being set holds Big_Theta f,X = (Big_Oh f,X) /\ (Big_Omega f,X)

proof end;

definition

let f be Real_Sequence;
let b be Element of NAT ;
func f taken_every b -> Real_Sequence means :Def18: :: ASYMPT_0:def 18
for n being Element of NAT holds it . n = f . (b * n);
existence
ex b₁ being Real_Sequence st
for n being Element of NAT holds b₁ . n = f . (b * n)

proof end;

uniqueness
for b₁, b₂ being Real_Sequence st ( for n being Element of NAT holds b₁ . n = f . (b * n) ) & ( for n being Element of NAT holds b₂ . n = f . (b * n) ) holds
b₁ = b₂

proof end;

end;

:: deftheorem Def18 defines taken_every ASYMPT_0:def 18 :

for f being Real_Sequence
for b being Element of NAT
for b₃ being Real_Sequence holds
( b₃ = f taken_every b iff for n being Element of NAT holds b₃ . n = f . (b * n) );

definition

let f be eventually-nonnegative Real_Sequence;
let b be Element of NAT ;
pred f is_smooth_wrt b means :Def19: :: ASYMPT_0:def 19
( f is eventually-nondecreasing & f taken_every b in Big_Oh f );

end;

:: deftheorem Def19 defines is_smooth_wrt ASYMPT_0:def 19 :

for f being eventually-nonnegative Real_Sequence
for b being Element of NAT holds
( f is_smooth_wrt b iff ( f is eventually-nondecreasing & f taken_every b in Big_Oh f ) );

definition

let f be eventually-nonnegative Real_Sequence;
attr f is smooth means :Def20: :: ASYMPT_0:def 20
for b being Element of NAT st b >= 2 holds
f is_smooth_wrt b;

end;

:: deftheorem Def20 defines smooth ASYMPT_0:def 20 :

for f being eventually-nonnegative Real_Sequence holds
( f is smooth iff for b being Element of NAT st b >= 2 holds
f is_smooth_wrt b );

theorem :: ASYMPT_0:37

for f being eventually-nonnegative Real_Sequence st ex b being Element of NAT st
( b >= 2 & f is_smooth_wrt b ) holds
f is smooth

proof end;

theorem Th38: :: ASYMPT_0:38

for f being 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_Oh f,{ (b |^ n) where n is Element of NAT : verum } holds
t in Big_Oh f

proof end;

theorem Th39: :: ASYMPT_0:39

for f being 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_Omega f,{ (b |^ n) where n is Element of NAT : verum } holds
t in Big_Omega f

proof end;

theorem :: ASYMPT_0:40

for f being 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

proof end;

definition

let X be non empty set ;
let F, G be FUNCTION_DOMAIN of X, REAL ;
func F + G -> FUNCTION_DOMAIN of X, REAL equals :: ASYMPT_0:def 21
{ t where t is Element of Funcs X,REAL : ex f, g being Element of Funcs X,REAL st
( f in F & g in G & ( for n being Element of X holds t . n = (f . n) + (g . n) ) ) } ;
coherence
{ t where t is Element of Funcs X,REAL : ex f, g being Element of Funcs X,REAL st
( f in F & g in G & ( for n being Element of X holds t . n = (f . n) + (g . n) ) ) } is FUNCTION_DOMAIN of X, REAL

proof end;

end;

:: deftheorem defines + ASYMPT_0:def 21 :

for X being non empty set
for F, G being FUNCTION_DOMAIN of X, REAL holds F + G = { t where t is Element of Funcs X,REAL : ex f, g being Element of Funcs X,REAL st
( f in F & g in G & ( for n being Element of X holds t . n = (f . n) + (g . n) ) ) } ;

definition

let X be non empty set ;
let F, G be FUNCTION_DOMAIN of X, REAL ;
func max F,G -> FUNCTION_DOMAIN of X, REAL equals :: ASYMPT_0:def 22
{ t where t is Element of Funcs X,REAL : ex f, g being Element of Funcs X,REAL st
( f in F & g in G & ( for n being Element of X holds t . n = max (f . n),(g . n) ) ) } ;
coherence
{ t where t is Element of Funcs X,REAL : ex f, g being Element of Funcs X,REAL st
( f in F & g in G & ( for n being Element of X holds t . n = max (f . n),(g . n) ) ) } is FUNCTION_DOMAIN of X, REAL

proof end;

end;

:: deftheorem defines max ASYMPT_0:def 22 :

for X being non empty set
for F, G being FUNCTION_DOMAIN of X, REAL holds max F,G = { t where t is Element of Funcs X,REAL : ex f, g being Element of Funcs X,REAL st
( f in F & g in G & ( for n being Element of X holds t . n = max (f . n),(g . n) ) ) } ;

theorem :: ASYMPT_0:41

for f, g being eventually-nonnegative Real_Sequence holds (Big_Oh f) + (Big_Oh g) = Big_Oh (f + g)

proof end;

theorem :: ASYMPT_0:42

for f, g being eventually-nonnegative Real_Sequence holds max (Big_Oh f),(Big_Oh g) = Big_Oh (max f,g)

proof end;

definition

let F, G be FUNCTION_DOMAIN of NAT , REAL ;
func F to_power G -> FUNCTION_DOMAIN of NAT , REAL equals :: ASYMPT_0:def 23
{ t where t is Element of Funcs NAT ,REAL : ex f, g being Element of Funcs NAT ,REAL ex N being Element of NAT st
( f in F & g in G & ( for n being Element of NAT st n >= N holds
t . n = (f . n) to_power (g . n) ) ) } ;
coherence
{ t where t is Element of Funcs NAT ,REAL : ex f, g being Element of Funcs NAT ,REAL ex N being Element of NAT st
( f in F & g in G & ( for n being Element of NAT st n >= N holds
t . n = (f . n) to_power (g . n) ) ) } is FUNCTION_DOMAIN of NAT , REAL

proof end;

end;

:: deftheorem defines to_power ASYMPT_0:def 23 :

for F, G being FUNCTION_DOMAIN of NAT , REAL holds F to_power G = { t where t is Element of Funcs NAT ,REAL : ex f, g being Element of Funcs NAT ,REAL ex N being Element of NAT st
( f in F & g in G & ( for n being Element of NAT st n >= N holds
t . n = (f . n) to_power (g . n) ) ) } ;