Theorem syli 37

Description: Syllogism inference with common nested antecedent. (Contributed by NM, 4-Nov-2004.)

Hypotheses

Ref	Expression
syli.1	⊢ (𝜓 → (𝜑 → 𝜒))
syli.2	⊢ (𝜒 → (𝜑 → 𝜃))

Assertion

Ref	Expression
syli	⊢ (𝜓 → (𝜑 → 𝜃))

Proof of Theorem syli

Step	Hyp	Ref	Expression
1		syli.1	. 2 ⊢ (𝜓 → (𝜑 → 𝜒))
2		syli.2	. . 3 ⊢ (𝜒 → (𝜑 → 𝜃))
3	2	com12 30	. 2 ⊢ (𝜑 → (𝜒 → 𝜃))
4	1, 3	sylcom 28	1 ⊢ (𝜓 → (𝜑 → 𝜃))

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:  ibd  178  bijadc  894  sbi2v  1947  elab3gf  2976  elreldm  5008  tz6.12c  5725  rntpos  6528  smores  6563  f1domg  7044  negm  10015