Theorem pm2.82 897

Description: Theorem *2.82 of [WhiteheadRussell] p. 108. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.82	|- ( ( ( ph \/ ps ) \/ ch ) -> ( ( ( ph \/ -. ch ) \/ th ) -> ( ( ph \/ ps ) \/ th ) ) )

Proof of Theorem pm2.82

Step	Hyp	Ref	Expression
1		pm2.24 121	. . . 4 |- ( ch -> ( -. ch -> ps ) )
2	1	orim2d 885	. . 3 |- ( ch -> ( ( ph \/ -. ch ) -> ( ph \/ ps ) ) )
3	2	jao1i 825	. 2 |- ( ( ( ph \/ ps ) \/ ch ) -> ( ( ph \/ -. ch ) -> ( ph \/ ps ) ) )
4	3	orim1d 884	1 |- ( ( ( ph \/ ps ) \/ ch ) -> ( ( ( ph \/ -. ch ) \/ th ) -> ( ( ph \/ ps ) \/ th ) ) )

Syntax hints:   -. wn 3   -> wi 4   \/ wo 383

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386

This theorem is referenced by: (None)