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Theorem wl-sbcom2d-lem2 37561
Description: Lemma used to prove wl-sbcom2d 37562. (Contributed by Wolf Lammen, 10-Aug-2019.) (New usage is discouraged.)
Assertion
Ref Expression
wl-sbcom2d-lem2 (¬ ∀𝑦 𝑦 = 𝑥 → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 ↔ ∀𝑥𝑦((𝑥 = 𝑢𝑦 = 𝑣) → 𝜑)))
Distinct variable groups:   𝑣,𝑢,𝑥   𝑦,𝑢,𝑣   𝜑,𝑢,𝑣
Allowed substitution hints:   𝜑(𝑥,𝑦)

Proof of Theorem wl-sbcom2d-lem2
StepHypRef Expression
1 id 22 . 2 (¬ ∀𝑦 𝑦 = 𝑥 → ¬ ∀𝑦 𝑦 = 𝑥)
2 naev 2060 . 2 (¬ ∀𝑦 𝑦 = 𝑥 → ¬ ∀𝑦 𝑦 = 𝑣)
3 naev 2060 . 2 (¬ ∀𝑦 𝑦 = 𝑥 → ¬ ∀𝑦 𝑦 = 𝑢)
4 naev 2060 . 2 (¬ ∀𝑦 𝑦 = 𝑥 → ¬ ∀𝑥 𝑥 = 𝑢)
51, 2, 3, 4wl-2sb6d 37559 1 (¬ ∀𝑦 𝑦 = 𝑥 → ([𝑢 / 𝑥][𝑣 / 𝑦]𝜑 ↔ ∀𝑥𝑦((𝑥 = 𝑢𝑦 = 𝑣) → 𝜑)))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 206  wa 395  wal 1538  [wsb 2064
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2007  ax-10 2141  ax-11 2157  ax-12 2177  ax-13 2377
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-tru 1543  df-ex 1780  df-nf 1784  df-sb 2065
This theorem is referenced by:  wl-sbcom2d  37562
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