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Theorem axextdist 32928
Description: ax-ext 2798 with distinctors instead of distinct variable restrictions. (Contributed by Scott Fenton, 13-Dec-2010.)
Assertion
Ref Expression
axextdist ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → (∀𝑧(𝑧𝑥𝑧𝑦) → 𝑥 = 𝑦))

Proof of Theorem axextdist
Dummy variable 𝑤 is distinct from all other variables.
StepHypRef Expression
1 nfnae 2453 . . . 4 𝑧 ¬ ∀𝑧 𝑧 = 𝑥
2 nfnae 2453 . . . 4 𝑧 ¬ ∀𝑧 𝑧 = 𝑦
31, 2nfan 1893 . . 3 𝑧(¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦)
4 nfcvf 3012 . . . . . 6 (¬ ∀𝑧 𝑧 = 𝑥𝑧𝑥)
54adantr 481 . . . . 5 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → 𝑧𝑥)
65nfcrd 2974 . . . 4 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → Ⅎ𝑧 𝑤𝑥)
7 nfcvf 3012 . . . . . 6 (¬ ∀𝑧 𝑧 = 𝑦𝑧𝑦)
87adantl 482 . . . . 5 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → 𝑧𝑦)
98nfcrd 2974 . . . 4 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → Ⅎ𝑧 𝑤𝑦)
106, 9nfbid 1896 . . 3 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → Ⅎ𝑧(𝑤𝑥𝑤𝑦))
11 elequ1 2114 . . . . 5 (𝑤 = 𝑧 → (𝑤𝑥𝑧𝑥))
12 elequ1 2114 . . . . 5 (𝑤 = 𝑧 → (𝑤𝑦𝑧𝑦))
1311, 12bibi12d 347 . . . 4 (𝑤 = 𝑧 → ((𝑤𝑥𝑤𝑦) ↔ (𝑧𝑥𝑧𝑦)))
1413a1i 11 . . 3 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → (𝑤 = 𝑧 → ((𝑤𝑥𝑤𝑦) ↔ (𝑧𝑥𝑧𝑦))))
153, 10, 14cbvald 2424 . 2 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → (∀𝑤(𝑤𝑥𝑤𝑦) ↔ ∀𝑧(𝑧𝑥𝑧𝑦)))
16 axextg 2800 . 2 (∀𝑤(𝑤𝑥𝑤𝑦) → 𝑥 = 𝑦)
1715, 16syl6bir 255 1 ((¬ ∀𝑧 𝑧 = 𝑥 ∧ ¬ ∀𝑧 𝑧 = 𝑦) → (∀𝑧(𝑧𝑥𝑧𝑦) → 𝑥 = 𝑦))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 207  wa 396  wal 1528  wnfc 2966
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1904  ax-6 1963  ax-7 2008  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2153  ax-12 2169  ax-13 2385  ax-ext 2798
This theorem depends on definitions:  df-bi 208  df-an 397  df-or 844  df-tru 1533  df-ex 1774  df-nf 1778  df-nfc 2968
This theorem is referenced by:  axextbdist  32929
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