Theorem jc 138

Description: Inference joining the consequents of two premises.

Hypotheses

Ref	Expression
jc.1	|- (ph -> ps)
jc.2	|- (ph -> ch)

Assertion

Ref	Expression
jc	|- (ph -> -. (ps -> -. ch))

Proof of Theorem jc

Step	Hyp	Ref	Expression
1		pm3.2im 122	. 2 |- (ps -> (ch -> -. (ps -> -. ch)))
2		jc.1	. 2 |- (ph -> ps)
3		jc.2	. 2 |- (ph -> ch)
4	1, 2, 3	sylc 68	1 |- (ph -> -. (ps -> -. ch))

Syntax hints:  -. wn 2   -> wi 3

This theorem is referenced by:  dfbi1 158  jca 288  equs4 1150

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

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