Theorem pm2.61ii 183

Description: Inference eliminating two antecedents. (Contributed by NM, 4-Jan-1993.) (Proof shortened by Josh Purinton, 29-Dec-2000.)

Hypotheses

Ref	Expression
pm2.61ii.1	⊢ (¬ 𝜑 → (¬ 𝜓 → 𝜒))
pm2.61ii.2	⊢ (𝜑 → 𝜒)
pm2.61ii.3	⊢ (𝜓 → 𝜒)

Assertion

Ref	Expression
pm2.61ii	⊢ 𝜒

Proof of Theorem pm2.61ii

Step	Hyp	Ref	Expression
1		pm2.61ii.2	. 2 ⊢ (𝜑 → 𝜒)
2		pm2.61ii.1	. . 3 ⊢ (¬ 𝜑 → (¬ 𝜓 → 𝜒))
3		pm2.61ii.3	. . 3 ⊢ (𝜓 → 𝜒)
4	2, 3	pm2.61d2 181	. 2 ⊢ (¬ 𝜑 → 𝜒)
5	1, 4	pm2.61i 182	1 ⊢ 𝜒

Syntax hints:  ¬ wn 3   → wi 4

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

This theorem is referenced by:  pm2.61iii  185  hbae  2436  pssnn  9097  alephadd  10494  axextnd  10508  axunnd  10513  axpownd  10518  axregndlem2  10520  axregnd  10521  axinfndlem1  10522  axinfnd  10523  2cshwcshw  14781  ressress  17211  frgrreg  30482  bj-hbaeb2  37144  hbae-o  39366  hbequid  39372  ax5eq  39395  ax5el  39400  odd2prm2  48209