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Theorem bj-axc10 33295
 Description: Alternate (shorter) proof of axc10 2349. One can prove a version with DV(x,y) without ax-13 2334, by using ax6ev 2023 instead of ax6e 2347. (Contributed by BJ, 31-Mar-2021.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-axc10 (∀𝑥(𝑥 = 𝑦 → ∀𝑥𝜑) → 𝜑)

Proof of Theorem bj-axc10
StepHypRef Expression
1 ax6e 2347 . . 3 𝑥 𝑥 = 𝑦
2 exim 1877 . . 3 (∀𝑥(𝑥 = 𝑦 → ∀𝑥𝜑) → (∃𝑥 𝑥 = 𝑦 → ∃𝑥𝑥𝜑))
31, 2mpi 20 . 2 (∀𝑥(𝑥 = 𝑦 → ∀𝑥𝜑) → ∃𝑥𝑥𝜑)
4 axc7e 2293 . 2 (∃𝑥𝑥𝜑𝜑)
53, 4syl 17 1 (∀𝑥(𝑥 = 𝑦 → ∀𝑥𝜑) → 𝜑)
 Colors of variables: wff setvar class Syntax hints:   → wi 4  ∀wal 1599  ∃wex 1823 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1839  ax-4 1853  ax-5 1953  ax-6 2021  ax-7 2055  ax-10 2135  ax-12 2163  ax-13 2334 This theorem depends on definitions:  df-bi 199  df-an 387  df-ex 1824 This theorem is referenced by: (None)
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