Theorem syl6ci 1495

Description: A syllogism inference combined with contraction. (Contributed by Alan Sare, 18-Mar-2012.)

Hypotheses

Ref	Expression
syl6ci.1	⊢ (𝜑 → (𝜓 → 𝜒))
syl6ci.2	⊢ (𝜑 → 𝜃)
syl6ci.3	⊢ (𝜒 → (𝜃 → 𝜏))

Assertion

Ref	Expression
syl6ci	⊢ (𝜑 → (𝜓 → 𝜏))

Proof of Theorem syl6ci

Step	Hyp	Ref	Expression
1		syl6ci.1	. 2 ⊢ (𝜑 → (𝜓 → 𝜒))
2		syl6ci.2	. . 3 ⊢ (𝜑 → 𝜃)
3	2	a1d 22	. 2 ⊢ (𝜑 → (𝜓 → 𝜃))
4		syl6ci.3	. 2 ⊢ (𝜒 → (𝜃 → 𝜏))
5	1, 3, 4	syl6c 66	1 ⊢ (𝜑 → (𝜓 → 𝜏))

This proof depends on syntax axioms:   → wi 4

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7

This theorem is used by:  ltxrlt  8391  ltnsym  8411  absle  11857  isumrpcl  12263  lealltlt1  16763  lealltlt2  16764