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Theorem naev 2095
Description: If some set variables can assume different values, then any two distinct set variables cannot always be the same. (Contributed by Wolf Lammen, 10-Aug-2019.)
Assertion
Ref Expression
naev (¬ ∀𝑥 𝑥 = 𝑦 → ¬ ∀𝑢 𝑢 = 𝑣)
Distinct variable group:   𝑣,𝑢

Proof of Theorem naev
StepHypRef Expression
1 aev 2092 . 2 (∀𝑢 𝑢 = 𝑣 → ∀𝑥 𝑥 = 𝑦)
21con3i 155 1 (¬ ∀𝑥 𝑥 = 𝑦 → ¬ ∀𝑢 𝑢 = 𝑣)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  ¬ wn 3  wi 4  wal 1568
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041
This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813
This theorem is used by:  naev2  2096  wl-sbcom2d-lem2  38256  wl-sbal1  38259  wl-sbal2  38260
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