Theorem 19.36imv 1951

Description: One direction of 19.36v 1998 that can be proven without ax-6 1974. (Contributed by Rohan Ridenour, 16-Apr-2022.) (Proof shortened by Wolf Lammen, 22-Sep-2024.)

Assertion

Ref	Expression
19.36imv	⊢ (∃𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓))

Distinct variable group:   𝜓,𝑥

Allowed substitution hint:   𝜑(𝑥)

Proof of Theorem 19.36imv

Step	Hyp	Ref	Expression
1		pm2.27 42	. . 3 ⊢ (𝜑 → ((𝜑 → 𝜓) → 𝜓))
2	1	aleximi 1838	. 2 ⊢ (∀𝑥𝜑 → (∃𝑥(𝜑 → 𝜓) → ∃𝑥𝜓))
3		ax5e 1918	. 2 ⊢ (∃𝑥𝜓 → 𝜓)
4	2, 3	syl6com 37	1 ⊢ (∃𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓))

Syntax hints:   → wi 4  ∀wal 1540  ∃wex 1786

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1916

This theorem depends on definitions:  df-bi 210  df-ex 1787

This theorem is referenced by:  19.36iv  1953