Theorem pm4.63 228

Description: Theorem *4.63 of [WhiteheadRussell] p. 120.

Assertion

Ref	Expression
pm4.63	|- (-. (ph -> -. ps) <-> (ph /\ ps))

Proof of Theorem pm4.63

Step	Hyp	Ref	Expression
1		df-an 225	. 2 |- ((ph /\ ps) <-> -. (ph -> -. ps))
2	1	bicomi 172	1 |- (-. (ph -> -. ps) <-> (ph /\ ps))

Syntax hints:  -. wn 2   -> wi 3   <-> wb 146   /\ wa 223

This theorem is referenced by:  pm4.67 241

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

This theorem depends on definitions:  df-bi 147  df-an 225

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