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Theorem xpss12 4473
Description: Subset theorem for cross product. Generalization of Theorem 101 of [Suppes] p. 52. (Contributed by NM, 26-Aug-1995.) (Proof shortened by Andrew Salmon, 27-Aug-2011.)
Assertion
Ref Expression
xpss12  |-  ( ( A  C_  B  /\  C  C_  D )  -> 
( A  X.  C
)  C_  ( B  X.  D ) )

Proof of Theorem xpss12
Dummy variables  x  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 ssel 2994 . . . 4  |-  ( A 
C_  B  ->  (
x  e.  A  ->  x  e.  B )
)
2 ssel 2994 . . . 4  |-  ( C 
C_  D  ->  (
y  e.  C  -> 
y  e.  D ) )
31, 2im2anan9 563 . . 3  |-  ( ( A  C_  B  /\  C  C_  D )  -> 
( ( x  e.  A  /\  y  e.  C )  ->  (
x  e.  B  /\  y  e.  D )
) )
43ssopab2dv 4041 . 2  |-  ( ( A  C_  B  /\  C  C_  D )  ->  { <. x ,  y
>.  |  ( x  e.  A  /\  y  e.  C ) }  C_  {
<. x ,  y >.  |  ( x  e.  B  /\  y  e.  D ) } )
5 df-xp 4377 . 2  |-  ( A  X.  C )  =  { <. x ,  y
>.  |  ( x  e.  A  /\  y  e.  C ) }
6 df-xp 4377 . 2  |-  ( B  X.  D )  =  { <. x ,  y
>.  |  ( x  e.  B  /\  y  e.  D ) }
74, 5, 63sstr4g 3041 1  |-  ( ( A  C_  B  /\  C  C_  D )  -> 
( A  X.  C
)  C_  ( B  X.  D ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 102    e. wcel 1434    C_ wss 2974   {copab 3846    X. cxp 4369
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 663  ax-5 1377  ax-7 1378  ax-gen 1379  ax-ie1 1423  ax-ie2 1424  ax-8 1436  ax-10 1437  ax-11 1438  ax-i12 1439  ax-bndl 1440  ax-4 1441  ax-17 1460  ax-i9 1464  ax-ial 1468  ax-i5r 1469  ax-ext 2064
This theorem depends on definitions:  df-bi 115  df-nf 1391  df-sb 1687  df-clab 2069  df-cleq 2075  df-clel 2078  df-nfc 2209  df-in 2980  df-ss 2987  df-opab 3848  df-xp 4377
This theorem is referenced by:  xpss  4474  xpss1  4476  xpss2  4477  djussxp  4509  ssxpbm  4786  ssrnres  4793  cossxp  4873  relrelss  4874  fssxp  5089  oprabss  5621  dmaddpi  6577  dmmulpi  6578  rexpssxrxp  7225  ltrelxr  7240  dfz2  8501  eucialg  10585
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