Theorem necon3bid 2408

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 2368	. 2 |- ( A =/= B <-> -. A = B )
2		necon3bid.1	. . 3 |- ( ph -> ( A = B <-> C = D ) )
3	2	necon3bbid 2407	. 2 |- ( ph -> ( -. A = B <-> C =/= D ) )
4	1, 3	bitrid 192	1 |- ( ph -> ( A =/= B <-> C =/= D ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 105   = wceq 1364   =/= wne 2367

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616

This theorem depends on definitions:  df-bi 117  df-ne 2368

This theorem is referenced by:  nebidc  2447  addneintrd  8231  addneintr2d  8232  negne0bd  8347  negned  8351  subne0d  8363  subne0ad  8365  subneintrd  8398  subneintr2d  8400  qapne  9730  xrlttri3  9889  xaddass2  9962  seqf1oglem1  10628  sqne0  10714  fihashneq0  10903  hashnncl  10904  cjne0  11090  absne0d  11369  sqrt2irraplemnn  12372  4sqlem11  12595  ringinvnz1ne0  13681  metn0  14698  perfectlem2  15320  lgsabs1  15364  neap0mkv  15800