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  7484  netap  7620  2oneel  7622  2omotaplemap  7623  2omotaplemst  7624  exmidapne  7626  xrlttri3  10199  hashdmprop2dom  11296  fun2dmnop0  11302  isnzr2  14491  umgrvad2edg  16452  eupth2lem3lem4fi  16714  3dom  17018  qdiff  17098  neapmkv  17118  neap0mkv  17119  ltlenmkv  17120