Theorem syl6d 73

Description: A nested syllogism deduction. Deduction associated with syl6 34. (Contributed by NM, 11-May-1993.) (Proof shortened by Josh Purinton, 29-Dec-2000.) (Proof shortened by Mel L. O'Cat, 2-Feb-2006.)

Hypotheses

Ref	Expression
syl6d.1	⊢ (𝜑 → (𝜓 → (𝜒 → 𝜃)))
syl6d.2	⊢ (𝜑 → (𝜃 → 𝜏))

Assertion

Ref	Expression
syl6d	⊢ (𝜑 → (𝜓 → (𝜒 → 𝜏)))

Proof of Theorem syl6d

Step	Hyp	Ref	Expression
1		syl6d.1	. 2 ⊢ (𝜑 → (𝜓 → (𝜒 → 𝜃)))
2		syl6d.2	. . 3 ⊢ (𝜑 → (𝜃 → 𝜏))
3	2	a1d 25	. 2 ⊢ (𝜑 → (𝜓 → (𝜃 → 𝜏)))
4	1, 3	syldd 70	1 ⊢ (𝜑 → (𝜓 → (𝜒 → 𝜏)))

Syntax hints:   → wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7

This theorem is referenced by:  syl8  74  sbi1  2380  omlimcl  7545  ltexprlem7  9743  axpre-sup  9869  caubnd  13946  ubthlem1  27110  poimirlem29  32608  ee13  37731  ssralv2  37758  rspsbc2  37765  truniALT  37772  stgoldbwt  40198