Theorem pm3.2ni 880

Description: Infer negated disjunction of negated premises. (Contributed by NM, 4-Apr-1995.)

Hypotheses

Ref	Expression
pm3.2ni.1	⊢ ¬ 𝜑
pm3.2ni.2	⊢ ¬ 𝜓

Assertion

Ref	Expression
pm3.2ni	⊢ ¬ (𝜑 ∨ 𝜓)

Proof of Theorem pm3.2ni

Step	Hyp	Ref	Expression
1		pm3.2ni.1	. 2 ⊢ ¬ 𝜑
2		id 22	. . 3 ⊢ (𝜑 → 𝜑)
3		pm3.2ni.2	. . . 4 ⊢ ¬ 𝜓
4	3	pm2.21i 119	. . 3 ⊢ (𝜓 → 𝜑)
5	2, 4	jaoi 857	. 2 ⊢ ((𝜑 ∨ 𝜓) → 𝜑)
6	1, 5	mto 197	1 ⊢ ¬ (𝜑 ∨ 𝜓)

Syntax hints:  ¬ wn 3   ∨ wo 847

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

This theorem depends on definitions:  df-bi 207  df-or 848

This theorem is referenced by:  3pm3.2ni  1490  snsn0non  6432  canthp1lem2  10541  recgt0ii  12025  xrltnr  13015  pnfnlt  13024  nltmnf  13025  smndex1n0mnd  18817  lhop  25946  2lgslem4  27342  nosgnn0  27595  axlowdimlem13  28930  clsk1indlem4  44076  clsk1indlem1  44077  dandysum2p2e4  47028