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Theorem iunss2 3963
Description: A subclass condition on the members of two indexed classes 
C ( x ) and  D ( y ) that implies a subclass relation on their indexed unions. Generalization of Proposition 8.6 of [TakeutiZaring] p. 59. Compare uniss2 3874. (Contributed by NM, 9-Dec-2004.)
Assertion
Ref Expression
iunss2  |-  ( A. x  e.  A  E. y  e.  B  C  C_  D  ->  U_ x  e.  A  C  C_  U_ y  e.  B  D )
Distinct variable groups:    x, y    x, B    y, C    x, D
Allowed substitution hints:    A( x, y)    B( y)    C( x)    D( y)

Proof of Theorem iunss2
StepHypRef Expression
1 ssiun 3960 . . 3  |-  ( E. y  e.  B  C  C_  D  ->  C  C_  U_ y  e.  B  D )
21ralimi 2631 . 2  |-  ( A. x  e.  A  E. y  e.  B  C  C_  D  ->  A. x  e.  A  C  C_  U_ y  e.  B  D )
3 iunss 3959 . 2  |-  ( U_ x  e.  A  C  C_ 
U_ y  e.  B  D 
<-> 
A. x  e.  A  C  C_  U_ y  e.  B  D )
42, 3sylibr 203 1  |-  ( A. x  e.  A  E. y  e.  B  C  C_  D  ->  U_ x  e.  A  C  C_  U_ y  e.  B  D )
Colors of variables: wff set class
Syntax hints:    -> wi 4   A.wral 2556   E.wrex 2557    C_ wss 3165   U_ciun 3921
This theorem is referenced by:  iunxdif2  3966  oaass  6575  odi  6593  omass  6594  oelim2  6609
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1536  ax-5 1547  ax-17 1606  ax-9 1644  ax-8 1661  ax-6 1715  ax-7 1720  ax-11 1727  ax-12 1878  ax-ext 2277
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-tru 1310  df-ex 1532  df-nf 1535  df-sb 1639  df-clab 2283  df-cleq 2289  df-clel 2292  df-nfc 2421  df-ral 2561  df-rex 2562  df-v 2803  df-in 3172  df-ss 3179  df-iun 3923
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