Theorem onirr 3097

Description: An ordinal number is not a member of itself. Theorem 7M(c) of [Enderton] p. 192.

Hypothesis

Ref	Expression
on.1	|- A e. On

Assertion

Ref	Expression
onirr	|- -. A e. A

Proof of Theorem onirr

Step	Hyp	Ref	Expression
1		on.1	. . 3 |- A e. On
2	1	onord 3095	. 2 |- Ord A
3		ordirr 2966	. 2 |- (Ord A -> -. A e. A)
4	2, 3	ax-mp 7	1 |- -. A e. A

Syntax hints:  -. wn 2   e. wcel 958  Ord word 2947  Oncon0 2948

This theorem is referenced by:  onssneli2 3102  onuninsuc 3108  oelim2 4222  pm54.43 4572

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 962  ax-gen 963  ax-8 964  ax-10 966  ax-11 967  ax-12 968  ax-13 969  ax-14 970  ax-17 971  ax-4 973  ax-5o 975  ax-6o 978  ax-9o 1123  ax-10o 1140  ax-16 1210  ax-11o 1218  ax-ext 1459  ax-sep 2703  ax-pow 2742  ax-pr 2779

This theorem depends on definitions:  df-bi 147  df-or 224  df-an 225  df-3an 777  df-ex 981  df-sb 1172  df-eu 1382  df-mo 1383  df-clab 1464  df-cleq 1469  df-clel 1472  df-ne 1587  df-ral 1649  df-rex 1650  df-v 1812  df-dif 2049  df-un 2050  df-in 2051  df-ss 2053  df-nul 2281  df-pw 2402  df-sn 2412  df-pr 2413  df-op 2416  df-uni 2504  df-br 2620  df-opab 2667  df-tr 2681  df-eprel 2832  df-po 2840  df-so 2850  df-fr 2917  df-we 2934  df-ord 2951  df-on 2952

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