Theorem pm2.01d 89

Description: Deduction based on reductio ad absurdum.

Hypothesis

Ref	Expression
pm2.01d.1	|- (ph -> (ps -> -. ps))

Assertion

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

Proof of Theorem pm2.01d

Step	Hyp	Ref	Expression
1		pm2.01d.1	. 2 |- (ph -> (ps -> -. ps))
2		pm2.01 88	. 2 |- ((ps -> -. ps) -> -. ps)
3	1, 2	syl 10	1 |- (ph -> -. ps)

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  pclem6 740  efrirr 2924  oalimcl 4187  omlimcl 4202  ivthlem7 7239  ivthlem7OLD 7248  cvnreft 10174

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

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