Theorem darii 2666

Description: "Darii", one of the syllogisms of Aristotelian logic. All 𝜑 is 𝜓, and some 𝜒 is 𝜑, therefore some 𝜒 is 𝜓. In Aristotelian notation, AII-1: MaP and SiM therefore SiP. For example, given "All rabbits have fur" and "Some pets are rabbits", therefore "Some pets have fur". Example from https://en.wikipedia.org/wiki/Syllogism. See dariiALT 2667 for a shorter proof requiring more axioms. (Contributed by David A. Wheeler, 24-Aug-2016.) Reduce dependencies on axioms. (Revised by BJ, 16-Sep-2022.)

Hypotheses

Ref	Expression
darii.maj	⊢ ∀𝑥(𝜑 → 𝜓)
darii.min	⊢ ∃𝑥(𝜒 ∧ 𝜑)

Assertion

Ref	Expression
darii	⊢ ∃𝑥(𝜒 ∧ 𝜓)

Proof of Theorem darii

Step	Hyp	Ref	Expression
1		darii.maj	. . 3 ⊢ ∀𝑥(𝜑 → 𝜓)
2		id 22	. . . . 5 ⊢ ((𝜑 → 𝜓) → (𝜑 → 𝜓))
3	2	anim2d 612	. . . 4 ⊢ ((𝜑 → 𝜓) → ((𝜒 ∧ 𝜑) → (𝜒 ∧ 𝜓)))
4	3	alimi 1814	. . 3 ⊢ (∀𝑥(𝜑 → 𝜓) → ∀𝑥((𝜒 ∧ 𝜑) → (𝜒 ∧ 𝜓)))
5	1, 4	ax-mp 5	. 2 ⊢ ∀𝑥((𝜒 ∧ 𝜑) → (𝜒 ∧ 𝜓))
6		darii.min	. 2 ⊢ ∃𝑥(𝜒 ∧ 𝜑)
7		exim 1836	. 2 ⊢ (∀𝑥((𝜒 ∧ 𝜑) → (𝜒 ∧ 𝜓)) → (∃𝑥(𝜒 ∧ 𝜑) → ∃𝑥(𝜒 ∧ 𝜓)))
8	5, 6, 7	mp2 9	1 ⊢ ∃𝑥(𝜒 ∧ 𝜓)

Syntax hints:   → wi 4   ∧ wa 396  ∀wal 1537  ∃wex 1782

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812

This theorem depends on definitions:  df-bi 206  df-an 397  df-ex 1783

This theorem is referenced by:  ferio  2668  datisi  2681  dimatis  2689