Theorem neeq2 2434

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 2248	. . 3 |- ( A = B -> ( C = A <-> C = B ) )
2	1	notbid 677	. 2 |- ( A = B -> ( -. C = A <-> -. C = B ) )
3		df-ne 2421	. 2 |- ( C =/= A <-> -. C = A )
4		df-ne 2421	. 2 |- ( C =/= B <-> -. C = B )
5	2, 3, 4	3bitr4g 223	1 |- ( A = B -> ( C =/= A <-> C =/= B ) )

This proof depends on syntax axioms:   -. wn 3   -> wi 4   <-> wb 105   = wceq 1402   =/= wne 2420

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 623  ax-in2 624  ax-5 1500  ax-gen 1502  ax-4 1563  ax-17 1579  ax-ext 2220

This proof depends on definitions:  df-bi 117  df-cleq 2231  df-ne 2421

This theorem is used by:  neeq2i  2436  neeq2d  2439  disji2  4122  fodjuomnilemdc  7485  netap  7621  2oneel  7623  2omotaplemap  7624  2omotaplemst  7625  exmidapne  7627  xrlttri3  10210  hashdmprop2dom  11312  fun2dmnop0  11318  isnzr2  14575  umgrvad2edg  16618  eupth2lem3lem4fi  16880  3dom  17184  qdiff  17265  neapmkv  17285  neap0mkv  17286  ltlenmkv  17287