Theorem necon1bbid 2833

Description: Contrapositive inference for inequality. (Contributed by NM, 31-Jan-2008.)

Hypothesis

Ref	Expression
necon1bbid.1	|- ( ph -> ( A =/= B <-> ps ) )

Assertion

Ref	Expression
necon1bbid	|- ( ph -> ( -. ps <-> A = B ) )

Proof of Theorem necon1bbid

Step	Hyp	Ref	Expression
1		df-ne 2795	. . 3 |- ( A =/= B <-> -. A = B )
2		necon1bbid.1	. . 3 |- ( ph -> ( A =/= B <-> ps ) )
3	1, 2	syl5bbr 274	. 2 |- ( ph -> ( -. A = B <-> ps ) )
4	3	con1bid 345	1 |- ( ph -> ( -. ps <-> A = B ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 196   = wceq 1483   =/= wne 2794

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-ne 2795

This theorem is referenced by:  necon4abid  2834  blssioo  22598  metdstri  22654  rrxmvallem  23187  dchrpt  24992  lgsquad3  25112  eupth2lem2  27079  lkrpssN  34450  dochshpsat  36743