Theorem neeq12i 2325

Description: Inference for inequality. (Contributed by NM, 24-Jul-2012.)

Hypotheses

Ref	Expression
neeq1i.1	|- A = B
neeq12i.2	|- C = D

Assertion

Ref	Expression
neeq12i	|- ( A =/= C <-> B =/= D )

Proof of Theorem neeq12i

Step	Hyp	Ref	Expression
1		neeq12i.2	. . 3 |- C = D
2	1	neeq2i 2324	. 2 |- ( A =/= C <-> A =/= D )
3		neeq1i.1	. . 3 |- A = B
4	3	neeq1i 2323	. 2 |- ( A =/= D <-> B =/= D )
5	2, 4	bitri 183	1 |- ( A =/= C <-> B =/= D )

Syntax hints:   <-> wb 104   = wceq 1331   =/= wne 2308

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 603  ax-in2 604  ax-5 1423  ax-gen 1425  ax-4 1487  ax-17 1506  ax-ext 2121

This theorem depends on definitions:  df-bi 116  df-cleq 2132  df-ne 2309

This theorem is referenced by:  3netr3g  2342  3netr4g  2343  setsmsbasg  12648  setsmsdsg  12649