Theorem necon3d 2408

Description: Contrapositive law deduction for inequality. (Contributed by NM, 10-Jun-2006.)

Hypothesis

Ref	Expression
necon3d.1	|- ( ph -> ( A = B -> C = D ) )

Assertion

Ref	Expression
necon3d	|- ( ph -> ( C =/= D -> A =/= B ) )

Proof of Theorem necon3d

Step	Hyp	Ref	Expression
1		necon3d.1	. . 3 |- ( ph -> ( A = B -> C = D ) )
2	1	necon3ad 2406	. 2 |- ( ph -> ( C =/= D -> -. A = B ) )
3		df-ne 2365	. 2 |- ( A =/= B <-> -. A = B )
4	2, 3	imbitrrdi 162	1 |- ( ph -> ( C =/= D -> A =/= B ) )

Syntax hints:   -. wn 3   -> wi 4   = wceq 1364   =/= wne 2364

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 2365

This theorem is referenced by:  necon3i  2412  pm13.18  2445  ssn0  3490  suppssfv  6128  suppssov1  6129  nnmord  6572  findcard2  6947  findcard2s  6948  addn0nid  8395  nn0n0n1ge2  9390  xnegdi  9937  efne0  11824  divgcdcoprmex  12243  pceulem  12435  pcqmul  12444  pcqcl  12447  pcaddlem  12480  pcadd  12481  grpinvnz  13146  ringelnzr  13686  lmodfopne  13825  lmodindp1  13927