Theorem exlimdh 1619

Description: Deduction from Theorem 19.23 of [Margaris] p. 90. (Contributed by NM, 28-Jan-1997.)

Hypotheses

Ref	Expression
exlimdh.1	⊢ (𝜑 → ∀𝑥𝜑)
exlimdh.2	⊢ (𝜒 → ∀𝑥𝜒)
exlimdh.3	⊢ (𝜑 → (𝜓 → 𝜒))

Assertion

Ref	Expression
exlimdh	⊢ (𝜑 → (∃𝑥𝜓 → 𝜒))

Proof of Theorem exlimdh

Step	Hyp	Ref	Expression
1		exlimdh.1	. . 3 ⊢ (𝜑 → ∀𝑥𝜑)
2		exlimdh.3	. . 3 ⊢ (𝜑 → (𝜓 → 𝜒))
3	1, 2	alrimih 1492	. 2 ⊢ (𝜑 → ∀𝑥(𝜓 → 𝜒))
4		exlimdh.2	. . 3 ⊢ (𝜒 → ∀𝑥𝜒)
5	4	19.23h 1521	. 2 ⊢ (∀𝑥(𝜓 → 𝜒) ↔ (∃𝑥𝜓 → 𝜒))
6	3, 5	sylib 122	1 ⊢ (𝜑 → (∃𝑥𝜓 → 𝜒))

Syntax hints:   → wi 4  ∀wal 1371  ∃wex 1515

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-5 1470  ax-gen 1472  ax-ie2 1517

This theorem depends on definitions:  df-bi 117

This theorem is referenced by:  exlimd  1620  exim  1622  exlimdv  1842  equs5  1852  cbvexdh  1950  exists2  2151