Theorem bj-eximcom 36958

Description: A commuted form of exim 1841 which is sometimes posited as an axiom in instuitionistic modal logic. Forward implication of 19.35 1884. Its converse is not intuitionistic. (Contributed by BJ, 9-Dec-2023.)

Assertion

Ref	Expression
bj-eximcom	⊢ (∃𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → ∃𝑥𝜓))

Proof of Theorem bj-eximcom

Step	Hyp	Ref	Expression
1		pm2.27 42	. . 3 ⊢ (𝜑 → ((𝜑 → 𝜓) → 𝜓))
2	1	aleximi 1839	. 2 ⊢ (∀𝑥𝜑 → (∃𝑥(𝜑 → 𝜓) → ∃𝑥𝜓))
3	2	com12 32	1 ⊢ (∃𝑥(𝜑 → 𝜓) → (∀𝑥𝜑 → ∃𝑥𝜓))

Syntax hints:   → wi 4  ∀wal 1545  ∃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

This theorem depends on definitions:  df-bi 208  df-ex 1787

This theorem is referenced by:  bj-nfimt  36964  bj-spimnfe  36965  bj-spimenfa  36966  bj-cbvalimdlem  36970  bj-cbveximdlem  36971  bj-wnf2  37064  bj-snsetex  37317  bj-axseprep  37428