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Theorem facubnd 11546
Description: An upper bound for the factorial function. (Contributed by Mario Carneiro, 15-Apr-2016.)
Assertion
Ref Expression
facubnd  |-  ( N  e.  NN0  ->  ( ! `
 N )  <_ 
( N ^ N
) )

Proof of Theorem facubnd
Dummy variables  m  k are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 fveq2 5687 . . . 4  |-  ( m  =  0  ->  ( ! `  m )  =  ( ! ` 
0 ) )
2 fac0 11524 . . . 4  |-  ( ! `
 0 )  =  1
31, 2syl6eq 2452 . . 3  |-  ( m  =  0  ->  ( ! `  m )  =  1 )
4 id 20 . . . . 5  |-  ( m  =  0  ->  m  =  0 )
54, 4oveq12d 6058 . . . 4  |-  ( m  =  0  ->  (
m ^ m )  =  ( 0 ^ 0 ) )
6 0cn 9040 . . . . 5  |-  0  e.  CC
7 exp0 11341 . . . . 5  |-  ( 0  e.  CC  ->  (
0 ^ 0 )  =  1 )
86, 7ax-mp 8 . . . 4  |-  ( 0 ^ 0 )  =  1
95, 8syl6eq 2452 . . 3  |-  ( m  =  0  ->  (
m ^ m )  =  1 )
103, 9breq12d 4185 . 2  |-  ( m  =  0  ->  (
( ! `  m
)  <_  ( m ^ m )  <->  1  <_  1 ) )
11 fveq2 5687 . . 3  |-  ( m  =  k  ->  ( ! `  m )  =  ( ! `  k ) )
12 id 20 . . . 4  |-  ( m  =  k  ->  m  =  k )
1312, 12oveq12d 6058 . . 3  |-  ( m  =  k  ->  (
m ^ m )  =  ( k ^
k ) )
1411, 13breq12d 4185 . 2  |-  ( m  =  k  ->  (
( ! `  m
)  <_  ( m ^ m )  <->  ( ! `  k )  <_  (
k ^ k ) ) )
15 fveq2 5687 . . 3  |-  ( m  =  ( k  +  1 )  ->  ( ! `  m )  =  ( ! `  ( k  +  1 ) ) )
16 id 20 . . . 4  |-  ( m  =  ( k  +  1 )  ->  m  =  ( k  +  1 ) )
1716, 16oveq12d 6058 . . 3  |-  ( m  =  ( k  +  1 )  ->  (
m ^ m )  =  ( ( k  +  1 ) ^
( k  +  1 ) ) )
1815, 17breq12d 4185 . 2  |-  ( m  =  ( k  +  1 )  ->  (
( ! `  m
)  <_  ( m ^ m )  <->  ( ! `  ( k  +  1 ) )  <_  (
( k  +  1 ) ^ ( k  +  1 ) ) ) )
19 fveq2 5687 . . 3  |-  ( m  =  N  ->  ( ! `  m )  =  ( ! `  N ) )
20 id 20 . . . 4  |-  ( m  =  N  ->  m  =  N )
2120, 20oveq12d 6058 . . 3  |-  ( m  =  N  ->  (
m ^ m )  =  ( N ^ N ) )
2219, 21breq12d 4185 . 2  |-  ( m  =  N  ->  (
( ! `  m
)  <_  ( m ^ m )  <->  ( ! `  N )  <_  ( N ^ N ) ) )
23 1le1 9606 . 2  |-  1  <_  1
24 faccl 11531 . . . . . . . 8  |-  ( k  e.  NN0  ->  ( ! `
 k )  e.  NN )
2524adantr 452 . . . . . . 7  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ! `  k
)  e.  NN )
2625nnred 9971 . . . . . 6  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ! `  k
)  e.  RR )
27 nn0re 10186 . . . . . . . 8  |-  ( k  e.  NN0  ->  k  e.  RR )
2827adantr 452 . . . . . . 7  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
k  e.  RR )
29 simpl 444 . . . . . . 7  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
k  e.  NN0 )
3028, 29reexpcld 11495 . . . . . 6  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( k ^ k
)  e.  RR )
31 nn0p1nn 10215 . . . . . . . . 9  |-  ( k  e.  NN0  ->  ( k  +  1 )  e.  NN )
3231adantr 452 . . . . . . . 8  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( k  +  1 )  e.  NN )
3332nnred 9971 . . . . . . 7  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( k  +  1 )  e.  RR )
3433, 29reexpcld 11495 . . . . . 6  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ( k  +  1 ) ^ k
)  e.  RR )
35 simpr 448 . . . . . 6  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ! `  k
)  <_  ( k ^ k ) )
36 nn0ge0 10203 . . . . . . . 8  |-  ( k  e.  NN0  ->  0  <_ 
k )
3736adantr 452 . . . . . . 7  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
0  <_  k )
3828lep1d 9898 . . . . . . 7  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
k  <_  ( k  +  1 ) )
39 leexp1a 11393 . . . . . . 7  |-  ( ( ( k  e.  RR  /\  ( k  +  1 )  e.  RR  /\  k  e.  NN0 )  /\  ( 0  <_  k  /\  k  <_  ( k  +  1 ) ) )  ->  ( k ^ k )  <_ 
( ( k  +  1 ) ^ k
) )
4028, 33, 29, 37, 38, 39syl32anc 1192 . . . . . 6  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( k ^ k
)  <_  ( (
k  +  1 ) ^ k ) )
4126, 30, 34, 35, 40letrd 9183 . . . . 5  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ! `  k
)  <_  ( (
k  +  1 ) ^ k ) )
4232nngt0d 9999 . . . . . 6  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
0  <  ( k  +  1 ) )
43 lemul1 9818 . . . . . 6  |-  ( ( ( ! `  k
)  e.  RR  /\  ( ( k  +  1 ) ^ k
)  e.  RR  /\  ( ( k  +  1 )  e.  RR  /\  0  <  ( k  +  1 ) ) )  ->  ( ( ! `  k )  <_  ( ( k  +  1 ) ^ k
)  <->  ( ( ! `
 k )  x.  ( k  +  1 ) )  <_  (
( ( k  +  1 ) ^ k
)  x.  ( k  +  1 ) ) ) )
4426, 34, 33, 42, 43syl112anc 1188 . . . . 5  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ( ! `  k )  <_  (
( k  +  1 ) ^ k )  <-> 
( ( ! `  k )  x.  (
k  +  1 ) )  <_  ( (
( k  +  1 ) ^ k )  x.  ( k  +  1 ) ) ) )
4541, 44mpbid 202 . . . 4  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ( ! `  k )  x.  (
k  +  1 ) )  <_  ( (
( k  +  1 ) ^ k )  x.  ( k  +  1 ) ) )
46 facp1 11526 . . . . 5  |-  ( k  e.  NN0  ->  ( ! `
 ( k  +  1 ) )  =  ( ( ! `  k )  x.  (
k  +  1 ) ) )
4746adantr 452 . . . 4  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ! `  (
k  +  1 ) )  =  ( ( ! `  k )  x.  ( k  +  1 ) ) )
4832nncnd 9972 . . . . 5  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( k  +  1 )  e.  CC )
4948, 29expp1d 11479 . . . 4  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ( k  +  1 ) ^ (
k  +  1 ) )  =  ( ( ( k  +  1 ) ^ k )  x.  ( k  +  1 ) ) )
5045, 47, 493brtr4d 4202 . . 3  |-  ( ( k  e.  NN0  /\  ( ! `  k )  <_  ( k ^
k ) )  -> 
( ! `  (
k  +  1 ) )  <_  ( (
k  +  1 ) ^ ( k  +  1 ) ) )
5150ex 424 . 2  |-  ( k  e.  NN0  ->  ( ( ! `  k )  <_  ( k ^
k )  ->  ( ! `  ( k  +  1 ) )  <_  ( ( k  +  1 ) ^
( k  +  1 ) ) ) )
5210, 14, 18, 22, 23, 51nn0ind 10322 1  |-  ( N  e.  NN0  ->  ( ! `
 N )  <_ 
( N ^ N
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 177    /\ wa 359    = wceq 1649    e. wcel 1721   class class class wbr 4172   ` cfv 5413  (class class class)co 6040   CCcc 8944   RRcr 8945   0cc0 8946   1c1 8947    + caddc 8949    x. cmul 8951    < clt 9076    <_ cle 9077   NNcn 9956   NN0cn0 10177   ^cexp 11337   !cfa 11521
This theorem is referenced by:  logfacubnd  20958
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1552  ax-5 1563  ax-17 1623  ax-9 1662  ax-8 1683  ax-13 1723  ax-14 1725  ax-6 1740  ax-7 1745  ax-11 1757  ax-12 1946  ax-ext 2385  ax-sep 4290  ax-nul 4298  ax-pow 4337  ax-pr 4363  ax-un 4660  ax-cnex 9002  ax-resscn 9003  ax-1cn 9004  ax-icn 9005  ax-addcl 9006  ax-addrcl 9007  ax-mulcl 9008  ax-mulrcl 9009  ax-mulcom 9010  ax-addass 9011  ax-mulass 9012  ax-distr 9013  ax-i2m1 9014  ax-1ne0 9015  ax-1rid 9016  ax-rnegex 9017  ax-rrecex 9018  ax-cnre 9019  ax-pre-lttri 9020  ax-pre-lttrn 9021  ax-pre-ltadd 9022  ax-pre-mulgt0 9023
This theorem depends on definitions:  df-bi 178  df-or 360  df-an 361  df-3or 937  df-3an 938  df-tru 1325  df-ex 1548  df-nf 1551  df-sb 1656  df-eu 2258  df-mo 2259  df-clab 2391  df-cleq 2397  df-clel 2400  df-nfc 2529  df-ne 2569  df-nel 2570  df-ral 2671  df-rex 2672  df-reu 2673  df-rab 2675  df-v 2918  df-sbc 3122  df-csb 3212  df-dif 3283  df-un 3285  df-in 3287  df-ss 3294  df-pss 3296  df-nul 3589  df-if 3700  df-pw 3761  df-sn 3780  df-pr 3781  df-tp 3782  df-op 3783  df-uni 3976  df-iun 4055  df-br 4173  df-opab 4227  df-mpt 4228  df-tr 4263  df-eprel 4454  df-id 4458  df-po 4463  df-so 4464  df-fr 4501  df-we 4503  df-ord 4544  df-on 4545  df-lim 4546  df-suc 4547  df-om 4805  df-xp 4843  df-rel 4844  df-cnv 4845  df-co 4846  df-dm 4847  df-rn 4848  df-res 4849  df-ima 4850  df-iota 5377  df-fun 5415  df-fn 5416  df-f 5417  df-f1 5418  df-fo 5419  df-f1o 5420  df-fv 5421  df-ov 6043  df-oprab 6044  df-mpt2 6045  df-2nd 6309  df-riota 6508  df-recs 6592  df-rdg 6627  df-er 6864  df-en 7069  df-dom 7070  df-sdom 7071  df-pnf 9078  df-mnf 9079  df-xr 9080  df-ltxr 9081  df-le 9082  df-sub 9249  df-neg 9250  df-nn 9957  df-n0 10178  df-z 10239  df-uz 10445  df-seq 11279  df-exp 11338  df-fac 11522
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