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Theorem bj-peano4 10080
Description: Remove from peano4 4320 dependency on ax-setind 4262. Therefore, it only requires core constructive axioms (albeit more of them). (Contributed by BJ, 28-Nov-2019.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-peano4  |-  ( ( A  e.  om  /\  B  e.  om )  ->  ( suc  A  =  suc  B  <->  A  =  B ) )

Proof of Theorem bj-peano4
StepHypRef Expression
1 3simpa 901 . . . . 5  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( A  e. 
om  /\  B  e.  om ) )
2 pm3.22 252 . . . . 5  |-  ( ( A  e.  om  /\  B  e.  om )  ->  ( B  e.  om  /\  A  e.  om )
)
3 bj-nnen2lp 10079 . . . . 5  |-  ( ( B  e.  om  /\  A  e.  om )  ->  -.  ( B  e.  A  /\  A  e.  B ) )
41, 2, 33syl 17 . . . 4  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  -.  ( B  e.  A  /\  A  e.  B ) )
5 sucidg 4153 . . . . . . . . . . . 12  |-  ( B  e.  om  ->  B  e.  suc  B )
6 eleq2 2101 . . . . . . . . . . . 12  |-  ( suc 
A  =  suc  B  ->  ( B  e.  suc  A  <-> 
B  e.  suc  B
) )
75, 6syl5ibrcom 146 . . . . . . . . . . 11  |-  ( B  e.  om  ->  ( suc  A  =  suc  B  ->  B  e.  suc  A
) )
8 elsucg 4141 . . . . . . . . . . 11  |-  ( B  e.  om  ->  ( B  e.  suc  A  <->  ( B  e.  A  \/  B  =  A ) ) )
97, 8sylibd 138 . . . . . . . . . 10  |-  ( B  e.  om  ->  ( suc  A  =  suc  B  ->  ( B  e.  A  \/  B  =  A
) ) )
109imp 115 . . . . . . . . 9  |-  ( ( B  e.  om  /\  suc  A  =  suc  B
)  ->  ( B  e.  A  \/  B  =  A ) )
11103adant1 922 . . . . . . . 8  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( B  e.  A  \/  B  =  A ) )
12 sucidg 4153 . . . . . . . . . . . 12  |-  ( A  e.  om  ->  A  e.  suc  A )
13 eleq2 2101 . . . . . . . . . . . 12  |-  ( suc 
A  =  suc  B  ->  ( A  e.  suc  A  <-> 
A  e.  suc  B
) )
1412, 13syl5ibcom 144 . . . . . . . . . . 11  |-  ( A  e.  om  ->  ( suc  A  =  suc  B  ->  A  e.  suc  B
) )
15 elsucg 4141 . . . . . . . . . . 11  |-  ( A  e.  om  ->  ( A  e.  suc  B  <->  ( A  e.  B  \/  A  =  B ) ) )
1614, 15sylibd 138 . . . . . . . . . 10  |-  ( A  e.  om  ->  ( suc  A  =  suc  B  ->  ( A  e.  B  \/  A  =  B
) ) )
1716imp 115 . . . . . . . . 9  |-  ( ( A  e.  om  /\  suc  A  =  suc  B
)  ->  ( A  e.  B  \/  A  =  B ) )
18173adant2 923 . . . . . . . 8  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( A  e.  B  \/  A  =  B ) )
1911, 18jca 290 . . . . . . 7  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( ( B  e.  A  \/  B  =  A )  /\  ( A  e.  B  \/  A  =  B )
) )
20 eqcom 2042 . . . . . . . . 9  |-  ( B  =  A  <->  A  =  B )
2120orbi2i 679 . . . . . . . 8  |-  ( ( B  e.  A  \/  B  =  A )  <->  ( B  e.  A  \/  A  =  B )
)
2221anbi1i 431 . . . . . . 7  |-  ( ( ( B  e.  A  \/  B  =  A
)  /\  ( A  e.  B  \/  A  =  B ) )  <->  ( ( B  e.  A  \/  A  =  B )  /\  ( A  e.  B  \/  A  =  B
) ) )
2319, 22sylib 127 . . . . . 6  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( ( B  e.  A  \/  A  =  B )  /\  ( A  e.  B  \/  A  =  B )
) )
24 ordir 730 . . . . . 6  |-  ( ( ( B  e.  A  /\  A  e.  B
)  \/  A  =  B )  <->  ( ( B  e.  A  \/  A  =  B )  /\  ( A  e.  B  \/  A  =  B
) ) )
2523, 24sylibr 137 . . . . 5  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( ( B  e.  A  /\  A  e.  B )  \/  A  =  B ) )
2625ord 643 . . . 4  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  ( -.  ( B  e.  A  /\  A  e.  B )  ->  A  =  B ) )
274, 26mpd 13 . . 3  |-  ( ( A  e.  om  /\  B  e.  om  /\  suc  A  =  suc  B )  ->  A  =  B )
28273expia 1106 . 2  |-  ( ( A  e.  om  /\  B  e.  om )  ->  ( suc  A  =  suc  B  ->  A  =  B ) )
29 suceq 4139 . 2  |-  ( A  =  B  ->  suc  A  =  suc  B )
3028, 29impbid1 130 1  |-  ( ( A  e.  om  /\  B  e.  om )  ->  ( suc  A  =  suc  B  <->  A  =  B ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    /\ wa 97    <-> wb 98    \/ wo 629    /\ w3a 885    = wceq 1243    e. wcel 1393   suc csuc 4102   omcom 4313
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545  ax-io 630  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-10 1396  ax-11 1397  ax-i12 1398  ax-bndl 1399  ax-4 1400  ax-13 1404  ax-14 1405  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022  ax-nul 3883  ax-pr 3944  ax-un 4170  ax-bd0 9933  ax-bdor 9936  ax-bdn 9937  ax-bdal 9938  ax-bdex 9939  ax-bdeq 9940  ax-bdel 9941  ax-bdsb 9942  ax-bdsep 10004  ax-infvn 10066
This theorem depends on definitions:  df-bi 110  df-3an 887  df-tru 1246  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-nfc 2167  df-ral 2311  df-rex 2312  df-rab 2315  df-v 2559  df-dif 2920  df-un 2922  df-in 2924  df-ss 2931  df-nul 3225  df-sn 3381  df-pr 3382  df-uni 3581  df-int 3616  df-suc 4108  df-iom 4314  df-bdc 9961  df-bj-ind 10051
This theorem is referenced by: (None)
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