Theorem neeq1 2353

Description: Equality theorem for inequality. (Contributed by NM, 19-Nov-1994.)

Assertion

Ref	Expression
neeq1	|- ( A = B -> ( A =/= C <-> B =/= C ) )

Proof of Theorem neeq1

Step	Hyp	Ref	Expression
1		eqeq1 2177	. . 3 |- ( A = B -> ( A = C <-> B = C ) )
2	1	notbid 662	. 2 |- ( A = B -> ( -. A = C <-> -. B = C ) )
3		df-ne 2341	. 2 |- ( A =/= C <-> -. A = C )
4		df-ne 2341	. 2 |- ( B =/= C <-> -. B = C )
5	2, 3, 4	3bitr4g 222	1 |- ( A = B -> ( A =/= C <-> B =/= C ) )

Syntax hints:   -. wn 3   -> wi 4   <-> wb 104   = wceq 1348   =/= wne 2340

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 609  ax-in2 610  ax-5 1440  ax-gen 1442  ax-4 1503  ax-17 1519  ax-ext 2152

This theorem depends on definitions:  df-bi 116  df-cleq 2163  df-ne 2341

This theorem is referenced by:  neeq1i  2355  neeq1d  2358  nelrdva  2937  disji2  3982  0inp0  4152  frecabcl  6378  fiintim  6906  eldju2ndl  7049  updjudhf  7056  xnn0nemnf  9209  uzn0  9502  xrnemnf  9734  xrnepnf  9735  ngtmnft  9774  xsubge0  9838  xposdif  9839  xleaddadd  9844  fztpval  10039  pcpre1  12246  pcqmul  12257  pcqcl  12260  fiinopn  12796  neapmkv  14099