Theorem necon3bid 2377

Description: Deduction from equality to inequality. (Contributed by NM, 23-Feb-2005.) (Proof shortened by Andrew Salmon, 25-May-2011.)

Hypothesis

Ref	Expression
necon3bid.1	|- ( ph -> ( A = B <-> C = D ) )

Assertion

Ref	Expression
necon3bid	|- ( ph -> ( A =/= B <-> C =/= D ) )

Proof of Theorem necon3bid

Step	Hyp	Ref	Expression
1		df-ne 2337	. 2 |- ( A =/= B <-> -. A = B )
2		necon3bid.1	. . 3 |- ( ph -> ( A = B <-> C = D ) )
3	2	necon3bbid 2376	. 2 |- ( ph -> ( -. A = B <-> C =/= D ) )
4	1, 3	syl5bb 191	1 |- ( ph -> ( A =/= B <-> C =/= D ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 104   = wceq 1343   =/= wne 2336

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 604  ax-in2 605

This theorem depends on definitions:  df-bi 116  df-ne 2337

This theorem is referenced by:  nebidc  2416  addneintrd  8086  addneintr2d  8087  negne0bd  8202  negned  8206  subne0d  8218  subne0ad  8220  subneintrd  8253  subneintr2d  8255  qapne  9577  xrlttri3  9733  xaddass2  9806  sqne0  10520  fihashneq0  10708  hashnncl  10709  cjne0  10850  absne0d  11129  sqrt2irraplemnn  12111  metn0  13018  lgsabs1  13580