Theorem darapti 2579

Description: "Darapti", one of the syllogisms of Aristotelian logic. All 𝜑 is 𝜓, all 𝜑 is 𝜒, and some 𝜑 exist, therefore some 𝜒 is 𝜓. (In Aristotelian notation, AAI-3: MaP and MaS therefore SiP.) For example, "All squares are rectangles" and "All squares are rhombuses", therefore "Some rhombuses are rectangles". (Contributed by David A. Wheeler, 28-Aug-2016.)

Hypotheses

Ref	Expression
darapti.maj	⊢ ∀𝑥(𝜑 → 𝜓)
darapti.min	⊢ ∀𝑥(𝜑 → 𝜒)
darapti.e	⊢ ∃𝑥𝜑

Assertion

Ref	Expression
darapti	⊢ ∃𝑥(𝜒 ∧ 𝜓)

Proof of Theorem darapti

Step	Hyp	Ref	Expression
1		darapti.e	. 2 ⊢ ∃𝑥𝜑
2		darapti.min	. . . 4 ⊢ ∀𝑥(𝜑 → 𝜒)
3	2	spi 2052	. . 3 ⊢ (𝜑 → 𝜒)
4		darapti.maj	. . . 4 ⊢ ∀𝑥(𝜑 → 𝜓)
5	4	spi 2052	. . 3 ⊢ (𝜑 → 𝜓)
6	3, 5	jca 554	. 2 ⊢ (𝜑 → (𝜒 ∧ 𝜓))
7	1, 6	eximii 1761	1 ⊢ ∃𝑥(𝜒 ∧ 𝜓)

Syntax hints:   → wi 4   ∧ wa 384  ∀wal 1478  ∃wex 1701

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836  ax-6 1885  ax-7 1932  ax-12 2044

This theorem depends on definitions:  df-bi 197  df-an 386  df-ex 1702

This theorem is referenced by: (None)