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Theorem dveeq2ALT 2489
Description: Alternate proof of dveeq2 2453, shorter but requiring ax-11 2189. (Contributed by NM, 2-Jan-2002.) (Revised by NM, 20-Jul-2015.) (New usage is discouraged.) (Proof modification is discouraged.)
Assertion
Ref Expression
dveeq2ALT (¬ ∀𝑥 𝑥 = 𝑦 → (𝑧 = 𝑦 → ∀𝑥 𝑧 = 𝑦))
Distinct variable group:   𝑥,𝑧

Proof of Theorem dveeq2ALT
Dummy variable 𝑤 is distinct from all other variables.
StepHypRef Expression
1 equequ2 2110 . 2 (𝑤 = 𝑦 → (𝑧 = 𝑤𝑧 = 𝑦))
21dvelimv 2487 1 (¬ ∀𝑥 𝑥 = 𝑦 → (𝑧 = 𝑦 → ∀𝑥 𝑧 = 𝑦))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wal 1628
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1869  ax-4 1884  ax-5 1990  ax-6 2056  ax-7 2092  ax-10 2173  ax-11 2189  ax-12 2202  ax-13 2407
This theorem depends on definitions:  df-bi 197  df-an 383  df-or 827  df-tru 1633  df-ex 1852  df-nf 1857
This theorem is referenced by: (None)
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