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Theorem 2on 6315
Description: Ordinal 2 is an ordinal number. (Contributed by NM, 18-Feb-2004.) (Proof shortened by Andrew Salmon, 12-Aug-2011.)
Assertion
Ref Expression
2on  |-  2o  e.  On

Proof of Theorem 2on
StepHypRef Expression
1 df-2o 6307 . 2  |-  2o  =  suc  1o
2 1on 6313 . . 3  |-  1o  e.  On
32onsuci 4427 . 2  |-  suc  1o  e.  On
41, 3eqeltri 2210 1  |-  2o  e.  On
Colors of variables: wff set class
Syntax hints:    e. wcel 1480   Oncon0 4280   suc csuc 4282   1oc1o 6299   2oc2o 6300
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 603  ax-in2 604  ax-io 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-13 1491  ax-14 1492  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2119  ax-sep 4041  ax-nul 4049  ax-pow 4093  ax-pr 4126  ax-un 4350
This theorem depends on definitions:  df-bi 116  df-tru 1334  df-nf 1437  df-sb 1736  df-clab 2124  df-cleq 2130  df-clel 2133  df-nfc 2268  df-ral 2419  df-rex 2420  df-v 2683  df-dif 3068  df-un 3070  df-in 3072  df-ss 3079  df-nul 3359  df-pw 3507  df-sn 3528  df-pr 3529  df-uni 3732  df-tr 4022  df-iord 4283  df-on 4285  df-suc 4288  df-1o 6306  df-2o 6307
This theorem is referenced by:  3on  6317
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