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Theorem axregndlem1 10013
 Description: Lemma for the Axiom of Regularity with no distinct variable conditions. Usage of this theorem is discouraged because it depends on ax-13 2391. (Contributed by NM, 3-Jan-2002.) (New usage is discouraged.)
Assertion
Ref Expression
axregndlem1 (∀𝑥 𝑥 = 𝑧 → (𝑥𝑦 → ∃𝑥(𝑥𝑦 ∧ ∀𝑧(𝑧𝑥 → ¬ 𝑧𝑦))))

Proof of Theorem axregndlem1
StepHypRef Expression
1 19.8a 2181 . 2 (𝑥𝑦 → ∃𝑥 𝑥𝑦)
2 nfae 2456 . . 3 𝑥𝑥 𝑥 = 𝑧
3 nfae 2456 . . . . . 6 𝑧𝑥 𝑥 = 𝑧
4 elirrv 9048 . . . . . . . . 9 ¬ 𝑥𝑥
5 elequ1 2121 . . . . . . . . 9 (𝑥 = 𝑧 → (𝑥𝑥𝑧𝑥))
64, 5mtbii 329 . . . . . . . 8 (𝑥 = 𝑧 → ¬ 𝑧𝑥)
76sps 2185 . . . . . . 7 (∀𝑥 𝑥 = 𝑧 → ¬ 𝑧𝑥)
87pm2.21d 121 . . . . . 6 (∀𝑥 𝑥 = 𝑧 → (𝑧𝑥 → ¬ 𝑧𝑦))
93, 8alrimi 2214 . . . . 5 (∀𝑥 𝑥 = 𝑧 → ∀𝑧(𝑧𝑥 → ¬ 𝑧𝑦))
109anim2i 619 . . . 4 ((𝑥𝑦 ∧ ∀𝑥 𝑥 = 𝑧) → (𝑥𝑦 ∧ ∀𝑧(𝑧𝑥 → ¬ 𝑧𝑦)))
1110expcom 417 . . 3 (∀𝑥 𝑥 = 𝑧 → (𝑥𝑦 → (𝑥𝑦 ∧ ∀𝑧(𝑧𝑥 → ¬ 𝑧𝑦))))
122, 11eximd 2217 . 2 (∀𝑥 𝑥 = 𝑧 → (∃𝑥 𝑥𝑦 → ∃𝑥(𝑥𝑦 ∧ ∀𝑧(𝑧𝑥 → ¬ 𝑧𝑦))))
131, 12syl5 34 1 (∀𝑥 𝑥 = 𝑧 → (𝑥𝑦 → ∃𝑥(𝑥𝑦 ∧ ∀𝑧(𝑧𝑥 → ¬ 𝑧𝑦))))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 399  ∀wal 1536  ∃wex 1781 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2116  ax-9 2124  ax-10 2145  ax-11 2161  ax-12 2178  ax-13 2391  ax-ext 2794  ax-sep 5179  ax-nul 5186  ax-pr 5307  ax-reg 9044 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-clab 2801  df-cleq 2815  df-clel 2894  df-nfc 2962  df-ral 3135  df-rex 3136  df-v 3471  df-dif 3911  df-un 3913  df-nul 4266  df-sn 4540  df-pr 4542 This theorem is referenced by:  axregndlem2  10014  axregnd  10015
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