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Theorem nnind 9760
Description: Principle of Mathematical Induction (inference schema). The first four hypotheses give us the substitution instances we need; the last two are the basis and the induction hypothesis. See nnaddcl 9764 for an example of its use. See nn0ind 10104 for induction on nonnegative integers and uzind 10099, uzind4 10272 for induction on an arbitrary set of upper integers. See indstr 10283 for strong induction. (Contributed by NM, 10-Jan-1997.) (Revised by Mario Carneiro, 16-Jun-2013.)
Hypotheses
Ref Expression
nnind.1  |-  ( x  =  1  ->  ( ph 
<->  ps ) )
nnind.2  |-  ( x  =  y  ->  ( ph 
<->  ch ) )
nnind.3  |-  ( x  =  ( y  +  1 )  ->  ( ph 
<->  th ) )
nnind.4  |-  ( x  =  A  ->  ( ph 
<->  ta ) )
nnind.5  |-  ps
nnind.6  |-  ( y  e.  NN  ->  ( ch  ->  th ) )
Assertion
Ref Expression
nnind  |-  ( A  e.  NN  ->  ta )
Distinct variable groups:    x, y    x, A    ps, x    ch, x    th, x    ta, x    ph, y
Allowed substitution hints:    ph( x)    ps( y)    ch( y)    th( y)    ta( y)    A( y)

Proof of Theorem nnind
StepHypRef Expression
1 1nn 9753 . . . . . 6  |-  1  e.  NN
2 nnind.5 . . . . . 6  |-  ps
3 nnind.1 . . . . . . 7  |-  ( x  =  1  ->  ( ph 
<->  ps ) )
43elrab 2924 . . . . . 6  |-  ( 1  e.  { x  e.  NN  |  ph }  <->  ( 1  e.  NN  /\  ps ) )
51, 2, 4mpbir2an 886 . . . . 5  |-  1  e.  { x  e.  NN  |  ph }
6 ssrab2 3259 . . . . . . . 8  |-  { x  e.  NN  |  ph }  C_  NN
76sseli 3177 . . . . . . 7  |-  ( y  e.  { x  e.  NN  |  ph }  ->  y  e.  NN )
8 peano2nn 9754 . . . . . . . . . 10  |-  ( y  e.  NN  ->  (
y  +  1 )  e.  NN )
98a1d 22 . . . . . . . . 9  |-  ( y  e.  NN  ->  (
y  e.  NN  ->  ( y  +  1 )  e.  NN ) )
10 nnind.6 . . . . . . . . 9  |-  ( y  e.  NN  ->  ( ch  ->  th ) )
119, 10anim12d 546 . . . . . . . 8  |-  ( y  e.  NN  ->  (
( y  e.  NN  /\ 
ch )  ->  (
( y  +  1 )  e.  NN  /\  th ) ) )
12 nnind.2 . . . . . . . . 9  |-  ( x  =  y  ->  ( ph 
<->  ch ) )
1312elrab 2924 . . . . . . . 8  |-  ( y  e.  { x  e.  NN  |  ph }  <->  ( y  e.  NN  /\  ch ) )
14 nnind.3 . . . . . . . . 9  |-  ( x  =  ( y  +  1 )  ->  ( ph 
<->  th ) )
1514elrab 2924 . . . . . . . 8  |-  ( ( y  +  1 )  e.  { x  e.  NN  |  ph }  <->  ( ( y  +  1 )  e.  NN  /\  th ) )
1611, 13, 153imtr4g 261 . . . . . . 7  |-  ( y  e.  NN  ->  (
y  e.  { x  e.  NN  |  ph }  ->  ( y  +  1 )  e.  { x  e.  NN  |  ph }
) )
177, 16mpcom 32 . . . . . 6  |-  ( y  e.  { x  e.  NN  |  ph }  ->  ( y  +  1 )  e.  { x  e.  NN  |  ph }
)
1817rgen 2609 . . . . 5  |-  A. y  e.  { x  e.  NN  |  ph }  ( y  +  1 )  e. 
{ x  e.  NN  |  ph }
19 peano5nni 9745 . . . . 5  |-  ( ( 1  e.  { x  e.  NN  |  ph }  /\  A. y  e.  {
x  e.  NN  |  ph }  ( y  +  1 )  e.  {
x  e.  NN  |  ph } )  ->  NN  C_ 
{ x  e.  NN  |  ph } )
205, 18, 19mp2an 653 . . . 4  |-  NN  C_  { x  e.  NN  |  ph }
2120sseli 3177 . . 3  |-  ( A  e.  NN  ->  A  e.  { x  e.  NN  |  ph } )
22 nnind.4 . . . 4  |-  ( x  =  A  ->  ( ph 
<->  ta ) )
2322elrab 2924 . . 3  |-  ( A  e.  { x  e.  NN  |  ph }  <->  ( A  e.  NN  /\  ta ) )
2421, 23sylib 188 . 2  |-  ( A  e.  NN  ->  ( A  e.  NN  /\  ta ) )
2524simprd 449 1  |-  ( A  e.  NN  ->  ta )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 176    /\ wa 358    = wceq 1623    e. wcel 1685   A.wral 2544   {crab 2548    C_ wss 3153  (class class class)co 5820   1c1 8734    + caddc 8736   NNcn 9742
This theorem is referenced by:  nnindALT  9761  nn1m1nn  9762  nnaddcl  9764  nnmulcl  9765  nnge1  9768  nnsub  9780  nneo  10091  peano5uzi  10096  uzindOLD  10102  nn0ind-raph  10108  ser1const  11098  expcllem  11110  expeq0  11128  seqcoll  11397  climcndslem2  12305  sqr2irr  12523  gcdmultiple  12725  rplpwr  12731  prmind2  12765  prmdvdsexp  12789  eulerthlem2  12846  pcmpt  12936  prmpwdvds  12947  vdwlem10  13033  mulgnnass  14591  imasdsf1olem  17933  ovolunlem1a  18851  ovolicc2lem3  18874  voliunlem1  18903  volsup  18909  dvexp  19298  plyco  19619  dgrcolem1  19650  vieta1  19688  emcllem6  20290  bposlem5  20523  2sqlem10  20609  dchrisum0flb  20655  subfacp1lem6  23123  cvmliftlem10  23232  incsequz  25869  bfplem1  25957  2nn0ind  26441  expmordi  26443  fmuldfeq  27124  stoweidlem20  27180  wallispilem4  27228  wallispi2lem1  27231  wallispi2lem2  27232
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1533  ax-5 1544  ax-17 1603  ax-9 1636  ax-8 1644  ax-13 1687  ax-14 1689  ax-6 1704  ax-7 1709  ax-11 1716  ax-12 1868  ax-ext 2265  ax-sep 4142  ax-nul 4150  ax-pr 4213  ax-un 4511  ax-1cn 8791
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-tru 1310  df-ex 1529  df-nf 1532  df-sb 1631  df-eu 2148  df-mo 2149  df-clab 2271  df-cleq 2277  df-clel 2280  df-nfc 2409  df-ne 2449  df-ral 2549  df-rex 2550  df-reu 2551  df-rab 2553  df-v 2791  df-sbc 2993  df-csb 3083  df-dif 3156  df-un 3158  df-in 3160  df-ss 3167  df-pss 3169  df-nul 3457  df-if 3567  df-pw 3628  df-sn 3647  df-pr 3648  df-tp 3649  df-op 3650  df-uni 3829  df-iun 3908  df-br 4025  df-opab 4079  df-mpt 4080  df-tr 4115  df-eprel 4304  df-id 4308  df-po 4313  df-so 4314  df-fr 4351  df-we 4353  df-ord 4394  df-on 4395  df-lim 4396  df-suc 4397  df-om 4656  df-xp 4694  df-rel 4695  df-cnv 4696  df-co 4697  df-dm 4698  df-rn 4699  df-res 4700  df-ima 4701  df-fun 5223  df-fn 5224  df-f 5225  df-f1 5226  df-fo 5227  df-f1o 5228  df-fv 5229  df-ov 5823  df-recs 6384  df-rdg 6419  df-nn 9743
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