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Theorem nn0le2is012 9666
Description: A nonnegative integer which is less than or equal to 2 is either 0 or 1 or 2. (Contributed by AV, 16-Mar-2019.)
Assertion
Ref Expression
nn0le2is012  |-  ( ( N  e.  NN0  /\  N  <_  2 )  -> 
( N  =  0  \/  N  =  1  \/  N  =  2 ) )

Proof of Theorem nn0le2is012
StepHypRef Expression
1 nn0z 9602 . . . 4  |-  ( N  e.  NN0  ->  N  e.  ZZ )
2 2z 9610 . . . 4  |-  2  e.  ZZ
3 zleloe 9629 . . . 4  |-  ( ( N  e.  ZZ  /\  2  e.  ZZ )  ->  ( N  <_  2  <->  ( N  <  2  \/  N  =  2 ) ) )
41, 2, 3sylancl 413 . . 3  |-  ( N  e.  NN0  ->  ( N  <_  2  <->  ( N  <  2  \/  N  =  2 ) ) )
5 zltlem1 9640 . . . . . . . . 9  |-  ( ( N  e.  ZZ  /\  2  e.  ZZ )  ->  ( N  <  2  <->  N  <_  ( 2  -  1 ) ) )
61, 2, 5sylancl 413 . . . . . . . 8  |-  ( N  e.  NN0  ->  ( N  <  2  <->  N  <_  ( 2  -  1 ) ) )
7 2m1e1 9360 . . . . . . . . . 10  |-  ( 2  -  1 )  =  1
87a1i 9 . . . . . . . . 9  |-  ( N  e.  NN0  ->  ( 2  -  1 )  =  1 )
98breq2d 4123 . . . . . . . 8  |-  ( N  e.  NN0  ->  ( N  <_  ( 2  -  1 )  <->  N  <_  1 ) )
106, 9bitrd 188 . . . . . . 7  |-  ( N  e.  NN0  ->  ( N  <  2  <->  N  <_  1 ) )
11 1z 9608 . . . . . . . . 9  |-  1  e.  ZZ
12 zleloe 9629 . . . . . . . . 9  |-  ( ( N  e.  ZZ  /\  1  e.  ZZ )  ->  ( N  <_  1  <->  ( N  <  1  \/  N  =  1 ) ) )
131, 11, 12sylancl 413 . . . . . . . 8  |-  ( N  e.  NN0  ->  ( N  <_  1  <->  ( N  <  1  \/  N  =  1 ) ) )
14 nn0lt10b 9664 . . . . . . . . . . . 12  |-  ( N  e.  NN0  ->  ( N  <  1  <->  N  = 
0 ) )
15 3mix1 1193 . . . . . . . . . . . 12  |-  ( N  =  0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) )
1614, 15biimtrdi 163 . . . . . . . . . . 11  |-  ( N  e.  NN0  ->  ( N  <  1  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
1716com12 30 . . . . . . . . . 10  |-  ( N  <  1  ->  ( N  e.  NN0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
18 3mix2 1194 . . . . . . . . . . 11  |-  ( N  =  1  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) )
1918a1d 22 . . . . . . . . . 10  |-  ( N  =  1  ->  ( N  e.  NN0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2017, 19jaoi 724 . . . . . . . . 9  |-  ( ( N  <  1  \/  N  =  1 )  ->  ( N  e. 
NN0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2120com12 30 . . . . . . . 8  |-  ( N  e.  NN0  ->  ( ( N  <  1  \/  N  =  1 )  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2213, 21sylbid 150 . . . . . . 7  |-  ( N  e.  NN0  ->  ( N  <_  1  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2310, 22sylbid 150 . . . . . 6  |-  ( N  e.  NN0  ->  ( N  <  2  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2423com12 30 . . . . 5  |-  ( N  <  2  ->  ( N  e.  NN0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
25 3mix3 1195 . . . . . 6  |-  ( N  =  2  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) )
2625a1d 22 . . . . 5  |-  ( N  =  2  ->  ( N  e.  NN0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2724, 26jaoi 724 . . . 4  |-  ( ( N  <  2  \/  N  =  2 )  ->  ( N  e. 
NN0  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
2827com12 30 . . 3  |-  ( N  e.  NN0  ->  ( ( N  <  2  \/  N  =  2 )  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
294, 28sylbid 150 . 2  |-  ( N  e.  NN0  ->  ( N  <_  2  ->  ( N  =  0  \/  N  =  1  \/  N  =  2 ) ) )
3029imp 124 1  |-  ( ( N  e.  NN0  /\  N  <_  2 )  -> 
( N  =  0  \/  N  =  1  \/  N  =  2 ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    <-> wb 105    \/ wo 716    \/ w3o 1004    = wceq 1398    e. wcel 2205   class class class wbr 4111  (class class class)co 6052   0cc0 8132   1c1 8133    < clt 8313    <_ cle 8314    - cmin 8449   2c2 9293   NN0cn0 9501   ZZcz 9582
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 619  ax-in2 620  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-13 2207  ax-14 2208  ax-ext 2216  ax-sep 4230  ax-pow 4289  ax-pr 4324  ax-un 4556  ax-setind 4661  ax-cnex 8223  ax-resscn 8224  ax-1cn 8225  ax-1re 8226  ax-icn 8227  ax-addcl 8228  ax-addrcl 8229  ax-mulcl 8230  ax-addcom 8232  ax-addass 8234  ax-distr 8236  ax-i2m1 8237  ax-0lt1 8238  ax-0id 8240  ax-rnegex 8241  ax-cnre 8243  ax-pre-ltirr 8244  ax-pre-ltwlin 8245  ax-pre-lttrn 8246  ax-pre-apti 8247  ax-pre-ltadd 8248
This theorem depends on definitions:  df-bi 117  df-3or 1006  df-3an 1007  df-tru 1401  df-fal 1404  df-nf 1510  df-sb 1812  df-eu 2085  df-mo 2086  df-clab 2221  df-cleq 2227  df-clel 2230  df-nfc 2375  df-ne 2415  df-nel 2510  df-ral 2527  df-rex 2528  df-reu 2529  df-rab 2531  df-v 2817  df-sbc 3045  df-dif 3215  df-un 3217  df-in 3219  df-ss 3226  df-pw 3673  df-sn 3697  df-pr 3698  df-op 3700  df-uni 3917  df-int 3952  df-br 4112  df-opab 4174  df-id 4416  df-xp 4757  df-rel 4758  df-cnv 4759  df-co 4760  df-dm 4761  df-iota 5314  df-fun 5356  df-fv 5362  df-riota 6005  df-ov 6055  df-oprab 6056  df-mpo 6057  df-pnf 8315  df-mnf 8316  df-xr 8317  df-ltxr 8318  df-le 8319  df-sub 8451  df-neg 8452  df-inn 9243  df-2 9301  df-n0 9502  df-z 9583
This theorem is referenced by:  xnn0le2is012  10205
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