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Theorem naecoms 2365
Description: A commutation rule for distinct variable specifiers. (Contributed by NM, 2-Jan-2002.)
Hypothesis
Ref Expression
naecoms.1 (¬ ∀𝑥 𝑥 = 𝑦𝜑)
Assertion
Ref Expression
naecoms (¬ ∀𝑦 𝑦 = 𝑥𝜑)

Proof of Theorem naecoms
StepHypRef Expression
1 aecom 2363 . 2 (∀𝑥 𝑥 = 𝑦 ↔ ∀𝑦 𝑦 = 𝑥)
2 naecoms.1 . 2 (¬ ∀𝑥 𝑥 = 𝑦𝜑)
31, 2sylnbir 323 1 (¬ ∀𝑦 𝑦 = 𝑥𝜑)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wal 1505
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1758  ax-4 1772  ax-5 1869  ax-6 1928  ax-7 1965  ax-10 2079  ax-12 2106  ax-13 2301
This theorem depends on definitions:  df-bi 199  df-an 388  df-ex 1743  df-nf 1747
This theorem is referenced by:  sb9  2485  eujustALT  2587  nfcvf2  2959  axpowndlem2  9818  wl-sbcom2d  34244  wl-mo2df  34253  wl-eudf  34255
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