Theorem pm2.01da 565

Description: Deduction based on reductio ad absurdum. (Contributed by Mario Carneiro, 9-Feb-2017.)

Hypothesis

Ref	Expression
pm2.01da.1	|- ( ( ph /\ ps ) -> -. ps )

Assertion

Ref	Expression
pm2.01da	|- ( ph -> -. ps )

Proof of Theorem pm2.01da

Step	Hyp	Ref	Expression
1		pm2.01da.1	. . 3 |- ( ( ph /\ ps ) -> -. ps )
2	1	ex 108	. 2 |- ( ph -> ( ps -> -. ps ) )
3	2	pm2.01d 548	1 |- ( ph -> -. ps )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 97

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia3 101  ax-in1 544

This theorem is referenced by:  efrirr  4090