Theorem neeq2 2381

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

Assertion

Ref	Expression
neeq2	|- ( A = B -> ( C =/= A <-> C =/= B ) )

Proof of Theorem neeq2

Step	Hyp	Ref	Expression
1		eqeq2 2206	. . 3 |- ( A = B -> ( C = A <-> C = B ) )
2	1	notbid 668	. 2 |- ( A = B -> ( -. C = A <-> -. C = B ) )
3		df-ne 2368	. 2 |- ( C =/= A <-> -. C = A )
4		df-ne 2368	. 2 |- ( C =/= B <-> -. C = B )
5	2, 3, 4	3bitr4g 223	1 |- ( A = B -> ( C =/= A <-> C =/= B ) )

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  ax-5 1461  ax-gen 1463  ax-4 1524  ax-17 1540  ax-ext 2178

This theorem depends on definitions:  df-bi 117  df-cleq 2189  df-ne 2368

This theorem is referenced by:  neeq2i  2383  neeq2d  2386  disji2  4027  fodjuomnilemdc  7211  netap  7323  2oneel  7325  2omotaplemap  7326  2omotaplemst  7327  exmidapne  7329  xrlttri3  9874  isnzr2  13750  neapmkv  15722  neap0mkv  15723  ltlenmkv  15724