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Theorem ax10fromc7 33627
Description: Rederivation of axiom ax-10 2021 from ax-c7 33617, ax-c4 33616, ax-c5 33615, ax-gen 1719 and propositional calculus. See axc7 2133 for the derivation of ax-c7 33617 from ax-10 2021. (Contributed by NM, 23-May-2008.) (Proof modification is discouraged.) (New usage is discouraged.)
Assertion
Ref Expression
ax10fromc7 (¬ ∀𝑥𝜑 → ∀𝑥 ¬ ∀𝑥𝜑)

Proof of Theorem ax10fromc7
StepHypRef Expression
1 ax-c4 33616 . . 3 (∀𝑥(∀𝑥 ¬ ∀𝑥𝑥𝜑 → ¬ ∀𝑥𝜑) → (∀𝑥 ¬ ∀𝑥𝑥𝜑 → ∀𝑥 ¬ ∀𝑥𝜑))
2 ax-c5 33615 . . . 4 (∀𝑥 ¬ ∀𝑥𝑥𝜑 → ¬ ∀𝑥𝑥𝜑)
3 ax-c4 33616 . . . . 5 (∀𝑥(∀𝑥𝜑 → ∀𝑥𝜑) → (∀𝑥𝜑 → ∀𝑥𝑥𝜑))
4 id 22 . . . . 5 (∀𝑥𝜑 → ∀𝑥𝜑)
53, 4mpg 1721 . . . 4 (∀𝑥𝜑 → ∀𝑥𝑥𝜑)
62, 5nsyl 135 . . 3 (∀𝑥 ¬ ∀𝑥𝑥𝜑 → ¬ ∀𝑥𝜑)
71, 6mpg 1721 . 2 (∀𝑥 ¬ ∀𝑥𝑥𝜑 → ∀𝑥 ¬ ∀𝑥𝜑)
8 ax-c7 33617 . 2 (¬ ∀𝑥 ¬ ∀𝑥𝑥𝜑 → ∀𝑥𝜑)
97, 8nsyl4 156 1 (¬ ∀𝑥𝜑 → ∀𝑥 ¬ ∀𝑥𝜑)
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wal 1478
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-c5 33615  ax-c4 33616  ax-c7 33617
This theorem is referenced by:  hba1-o  33629  axc5c711  33650  equidq  33656
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