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Theorem elnelneqd 42954
Description: Two classes are not equal if there is an element of one which is not an element of the other. (Contributed by Rohan Ridenour, 11-Aug-2023.)
Hypotheses
Ref Expression
elnelneqd.1 (𝜑𝐶𝐴)
elnelneqd.2 (𝜑 → ¬ 𝐶𝐵)
Assertion
Ref Expression
elnelneqd (𝜑 → ¬ 𝐴 = 𝐵)

Proof of Theorem elnelneqd
StepHypRef Expression
1 elnelneqd.2 . 2 (𝜑 → ¬ 𝐶𝐵)
2 elnelneqd.1 . . . 4 (𝜑𝐶𝐴)
32adantr 482 . . 3 ((𝜑𝐴 = 𝐵) → 𝐶𝐴)
4 simpr 486 . . 3 ((𝜑𝐴 = 𝐵) → 𝐴 = 𝐵)
53, 4eleqtrd 2836 . 2 ((𝜑𝐴 = 𝐵) → 𝐶𝐵)
61, 5mtand 815 1 (𝜑 → ¬ 𝐴 = 𝐵)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wa 397   = wceq 1542  wcel 2107
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-ext 2704
This theorem depends on definitions:  df-bi 206  df-an 398  df-ex 1783  df-cleq 2725  df-clel 2811
This theorem is referenced by:  mnuprdlem1  43031  mnuprdlem2  43032
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