Theorem ax4fromc4 36645

Description: Rederivation of Axiom ax-4 1817 from ax-c4 36635, ax-c5 36634, ax-gen 1803 and minimal implicational calculus { ax-mp 5, ax-1 6, ax-2 7 }. See axc4 2320 for the derivation of ax-c4 36635 from ax-4 1817. (Contributed by NM, 23-May-2008.) (Proof modification is discouraged.) Use ax-4 1817 instead. (New usage is discouraged.)

Assertion

Ref	Expression
ax4fromc4	⊢ (∀𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → ∀𝑥𝜓))

Proof of Theorem ax4fromc4

Step	Hyp	Ref	Expression
1		ax-c4 36635	. . 3 ⊢ (∀𝑥(∀𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓)) → (∀𝑥(𝜑 → 𝜓) → ∀𝑥(∀𝑥𝜑 → 𝜓)))
2		ax-c5 36634	. . . 4 ⊢ (∀𝑥𝜑 → 𝜑)
3		ax-c5 36634	. . . 4 ⊢ (∀𝑥(𝜑 → 𝜓) → (𝜑 → 𝜓))
4	2, 3	syl5 34	. . 3 ⊢ (∀𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓))
5	1, 4	mpg 1805	. 2 ⊢ (∀𝑥(𝜑 → 𝜓) → ∀𝑥(∀𝑥𝜑 → 𝜓))
6		ax-c4 36635	. 2 ⊢ (∀𝑥(∀𝑥𝜑 → 𝜓) → (∀𝑥𝜑 → ∀𝑥𝜓))
7	5, 6	syl 17	1 ⊢ (∀𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → ∀𝑥𝜓))

Syntax hints:   → wi 4  ∀wal 1541

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-gen 1803  ax-c5 36634  ax-c4 36635

This theorem is referenced by: (None)