Theorem necon3bid 2388

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 2348	. 2 |- ( A =/= B <-> -. A = B )
2		necon3bid.1	. . 3 |- ( ph -> ( A = B <-> C = D ) )
3	2	necon3bbid 2387	. 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 1353   =/= wne 2347

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 614  ax-in2 615

This theorem depends on definitions:  df-bi 117  df-ne 2348

This theorem is referenced by:  nebidc  2427  addneintrd  8145  addneintr2d  8146  negne0bd  8261  negned  8265  subne0d  8277  subne0ad  8279  subneintrd  8312  subneintr2d  8314  qapne  9639  xrlttri3  9797  xaddass2  9870  sqne0  10586  fihashneq0  10774  hashnncl  10775  cjne0  10917  absne0d  11196  sqrt2irraplemnn  12179  ringinvnz1ne0  13226  metn0  13881  lgsabs1  14443  neap0mkv  14819