Theorem necon3bbid 2245

Description: Deduction from equality to inequality. (Contributed by NM, 2-Jun-2007.)

Hypothesis

Ref	Expression
necon3bbid.1	|- ( ph -> ( ps <-> A = B ) )

Assertion

Ref	Expression
necon3bbid	|- ( ph -> ( -. ps <-> A =/= B ) )

Proof of Theorem necon3bbid

Step	Hyp	Ref	Expression
1		necon3bbid.1	. . . 4 |- ( ph -> ( ps <-> A = B ) )
2	1	bicomd 129	. . 3 |- ( ph -> ( A = B <-> ps ) )
3	2	necon3abid 2244	. 2 |- ( ph -> ( A =/= B <-> -. ps ) )
4	3	bicomd 129	1 |- ( ph -> ( -. ps <-> A =/= B ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 98   = wceq 1243   =/= wne 2204

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-in1 544  ax-in2 545

This theorem depends on definitions:  df-bi 110  df-ne 2206

This theorem is referenced by:  necon3bid  2246  eldifsn  3495