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Theorem peano3 4613
Description: The successor of any natural number is not zero. One of Peano's five postulates for arithmetic. Proposition 7.30(3) of [TakeutiZaring] p. 42. (Contributed by NM, 3-Sep-2003.)
Assertion
Ref Expression
peano3 (𝐴 ∈ ω → suc 𝐴 ≠ ∅)

Proof of Theorem peano3
StepHypRef Expression
1 nsuceq0g 4436 1 (𝐴 ∈ ω → suc 𝐴 ≠ ∅)
Colors of variables: wff set class
Syntax hints:  wi 4  wcel 2160  wne 2360  c0 3437  suc csuc 4383  ωcom 4607
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 615  ax-in2 616  ax-io 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-ext 2171
This theorem depends on definitions:  df-bi 117  df-tru 1367  df-nf 1472  df-sb 1774  df-clab 2176  df-cleq 2182  df-clel 2185  df-nfc 2321  df-ne 2361  df-v 2754  df-dif 3146  df-un 3148  df-nul 3438  df-sn 3613  df-suc 4389
This theorem is referenced by:  nndceq0  4635  frecabcl  6425  frecsuclem  6432  nnsucsssuc  6518  php5  6887  findcard2  6918  findcard2s  6919  omp1eomlem  7124  ctmlemr  7138  nnsf  15233  peano4nninf  15234
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