Theorem xpsndisj 5191

Description: Cross products with two different singletons are disjoint. (Contributed by NM, 28-Jul-2004.)

Assertion

Ref	Expression
xpsndisj	|- ( B =/= D -> ( ( A X. { B } ) i^i ( C X. { D } ) ) = (/) )

Proof of Theorem xpsndisj

Step	Hyp	Ref	Expression
1		disjsn2 3754	. 2 |- ( B =/= D -> ( { B } i^i { D } ) = (/) )
2		xpdisj2 5190	. 2 |- ( ( { B } i^i { D } ) = (/) -> ( ( A X. { B } ) i^i ( C X. { D } ) ) = (/) )
3	1, 2	syl 14	1 |- ( B =/= D -> ( ( A X. { B } ) i^i ( C X. { D } ) ) = (/) )

Syntax hints:   -> wi 4   = wceq 1398   =/= wne 2414   i^i cin 3212   (/)c0 3510   {csn 3691   X. cxp 4749

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 619  ax-in2 620  ax-io 717  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-10 1554  ax-11 1555  ax-i12 1556  ax-bndl 1558  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-14 2208  ax-ext 2216  ax-sep 4230  ax-pow 4289  ax-pr 4324

This theorem depends on definitions:  df-bi 117  df-3an 1007  df-tru 1401  df-fal 1404  df-nf 1510  df-sb 1812  df-eu 2085  df-mo 2086  df-clab 2221  df-cleq 2227  df-clel 2230  df-nfc 2375  df-ne 2415  df-ral 2527  df-rex 2528  df-v 2817  df-dif 3215  df-un 3217  df-in 3219  df-ss 3226  df-nul 3511  df-pw 3673  df-sn 3697  df-pr 3698  df-op 3700  df-br 4112  df-opab 4174  df-xp 4757  df-rel 4758  df-cnv 4759

This theorem is referenced by:  xp01disj  6668