Theorem 19.41rg 45144

Description: Closed form of right-to-left implication of 19.41 2277, Theorem 19.41 of [Margaris] p. 90. Derived from 19.41rgVD 45495. (Contributed by Alan Sare, 8-Feb-2014.) (Proof modification is discouraged.) (New usage is discouraged.)

Assertion

Ref	Expression
19.41rg	⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → ((∃𝑥𝜑 ∧ 𝜓) → ∃𝑥(𝜑 ∧ 𝜓)))

Proof of Theorem 19.41rg

Step	Hyp	Ref	Expression
1		sp 2225	. . . 4 ⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → (𝜓 → ∀𝑥𝜓))
2		pm3.21 476	. . . . . . 7 ⊢ (𝜓 → (𝜑 → (𝜑 ∧ 𝜓)))
3	2	a1i 11	. . . . . 6 ⊢ ((𝜓 → ∀𝑥𝜓) → (𝜓 → (𝜑 → (𝜑 ∧ 𝜓))))
4	3	al2imi 1842	. . . . 5 ⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → (∀𝑥𝜓 → ∀𝑥(𝜑 → (𝜑 ∧ 𝜓))))
5		exim 1861	. . . . 5 ⊢ (∀𝑥(𝜑 → (𝜑 ∧ 𝜓)) → (∃𝑥𝜑 → ∃𝑥(𝜑 ∧ 𝜓)))
6	4, 5	syl6 36	. . . 4 ⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → (∀𝑥𝜓 → (∃𝑥𝜑 → ∃𝑥(𝜑 ∧ 𝜓))))
7	1, 6	syld 48	. . 3 ⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → (𝜓 → (∃𝑥𝜑 → ∃𝑥(𝜑 ∧ 𝜓))))
8	7	com23 87	. 2 ⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → (∃𝑥𝜑 → (𝜓 → ∃𝑥(𝜑 ∧ 𝜓))))
9	8	impd 415	1 ⊢ (∀𝑥(𝜓 → ∀𝑥𝜓) → ((∃𝑥𝜑 ∧ 𝜓) → ∃𝑥(𝜑 ∧ 𝜓)))

Syntax hints:   → wi 4   ∧ wa 400  ∀wal 1565  ∃wex 1806

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-12 2219

This theorem depends on definitions:  df-bi 210  df-an 401  df-ex 1807

This theorem is referenced by:  ax6e2nd  45152  ax6e2ndVD  45501  ax6e2ndALT  45523