Theorem imim12d 74

Description: Deduction combining antecedents and consequents. (Contributed by NM, 7-Aug-1994.) (Proof shortened by O'Cat, 30-Oct-2011.)

Hypotheses

Ref	Expression
imim12d.1	⊢ (𝜑 → (𝜓 → 𝜒))
imim12d.2	⊢ (𝜑 → (𝜃 → 𝜏))

Assertion

Ref	Expression
imim12d	⊢ (𝜑 → ((𝜒 → 𝜃) → (𝜓 → 𝜏)))

Proof of Theorem imim12d

Step	Hyp	Ref	Expression
1		imim12d.1	. 2 ⊢ (𝜑 → (𝜓 → 𝜒))
2		imim12d.2	. . 3 ⊢ (𝜑 → (𝜃 → 𝜏))
3	2	imim2d 54	. 2 ⊢ (𝜑 → ((𝜒 → 𝜃) → (𝜒 → 𝜏)))
4	1, 3	syl5d 68	1 ⊢ (𝜑 → ((𝜒 → 𝜃) → (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:  imim1d  75  equveli  1812  hbsb4t  2073  mo23  2128  rspcimdv  2930  r19.29uz  11774  txlm  15471  metcnpi3  15709  addcncntoplem  15753  cnplimcim  15859  setindis  17164  bdsetindis  17166  bj-findis  17176