Theorem pm3.1 314

Description: Theorem *3.1 of [WhiteheadRussell] p. 111.

Assertion

Ref	Expression
pm3.1	|- ((ph /\ ps) -> -. (-. ph \/ -. ps))

Proof of Theorem pm3.1

Step	Hyp	Ref	Expression
1		anor 304	. 2 |- ((ph /\ ps) <-> -. (-. ph \/ -. ps))
2	1	biimp 151	1 |- ((ph /\ ps) -> -. (-. ph \/ -. ps))

Syntax hints:  -. wn 2   -> wi 3   \/ wo 222   /\ wa 223

This theorem is referenced by:  pm3.14 318

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-or 224  df-an 225

Copyright terms: Public domain