Theorem pm3.2ni 759

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

Hypotheses

Ref	Expression
pm3.2ni.1	|- -. ph
pm3.2ni.2	|- -. ps

Assertion

Ref	Expression
pm3.2ni	|- -. ( ph \/ ps )

Proof of Theorem pm3.2ni

Step	Hyp	Ref	Expression
1		pm3.2ni.1	. 2 |- -. ph
2		id 19	. . 3 |- ( ph -> ph )
3		pm3.2ni.2	. . . 4 |- -. ps
4	3	pm2.21i 607	. . 3 |- ( ps -> ph )
5	2, 4	jaoi 668	. 2 |- ( ( ph \/ ps ) -> ph )
6	1, 5	mto 620	1 |- -. ( ph \/ ps )

Syntax hints:   -. wn 3   \/ wo 661

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-io 662

This theorem depends on definitions:  df-bi 115

This theorem is referenced by:  xrltnr  8855  pnfnlt  8862  nltmnf  8863