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Theorem ssin 3195
Description: Subclass of intersection. Theorem 2.8(vii) of [Monk1] p. 26. (Contributed by NM, 15-Jun-2004.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
Assertion
Ref Expression
ssin  |-  ( ( A  C_  B  /\  A  C_  C )  <->  A  C_  ( B  i^i  C ) )

Proof of Theorem ssin
Dummy variable  x is distinct from all other variables.
StepHypRef Expression
1 elin 3156 . . . . 5  |-  ( x  e.  ( B  i^i  C )  <->  ( x  e.  B  /\  x  e.  C ) )
21imbi2i 224 . . . 4  |-  ( ( x  e.  A  ->  x  e.  ( B  i^i  C ) )  <->  ( x  e.  A  ->  ( x  e.  B  /\  x  e.  C ) ) )
32albii 1400 . . 3  |-  ( A. x ( x  e.  A  ->  x  e.  ( B  i^i  C ) )  <->  A. x ( x  e.  A  ->  (
x  e.  B  /\  x  e.  C )
) )
4 jcab 568 . . . 4  |-  ( ( x  e.  A  -> 
( x  e.  B  /\  x  e.  C
) )  <->  ( (
x  e.  A  ->  x  e.  B )  /\  ( x  e.  A  ->  x  e.  C ) ) )
54albii 1400 . . 3  |-  ( A. x ( x  e.  A  ->  ( x  e.  B  /\  x  e.  C ) )  <->  A. x
( ( x  e.  A  ->  x  e.  B )  /\  (
x  e.  A  ->  x  e.  C )
) )
6 19.26 1411 . . 3  |-  ( A. x ( ( x  e.  A  ->  x  e.  B )  /\  (
x  e.  A  ->  x  e.  C )
)  <->  ( A. x
( x  e.  A  ->  x  e.  B )  /\  A. x ( x  e.  A  ->  x  e.  C )
) )
73, 5, 63bitrri 205 . 2  |-  ( ( A. x ( x  e.  A  ->  x  e.  B )  /\  A. x ( x  e.  A  ->  x  e.  C ) )  <->  A. x
( x  e.  A  ->  x  e.  ( B  i^i  C ) ) )
8 dfss2 2989 . . 3  |-  ( A 
C_  B  <->  A. x
( x  e.  A  ->  x  e.  B ) )
9 dfss2 2989 . . 3  |-  ( A 
C_  C  <->  A. x
( x  e.  A  ->  x  e.  C ) )
108, 9anbi12i 448 . 2  |-  ( ( A  C_  B  /\  A  C_  C )  <->  ( A. x ( x  e.  A  ->  x  e.  B )  /\  A. x ( x  e.  A  ->  x  e.  C ) ) )
11 dfss2 2989 . 2  |-  ( A 
C_  ( B  i^i  C )  <->  A. x ( x  e.  A  ->  x  e.  ( B  i^i  C
) ) )
127, 10, 113bitr4i 210 1  |-  ( ( A  C_  B  /\  A  C_  C )  <->  A  C_  ( B  i^i  C ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 102    <-> wb 103   A.wal 1283    e. wcel 1434    i^i cin 2973    C_ wss 2974
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-tru 1288  df-nf 1391  df-sb 1687  df-clab 2069  df-cleq 2075  df-clel 2078  df-nfc 2209  df-v 2604  df-in 2980  df-ss 2987
This theorem is referenced by:  ssini  3196  ssind  3197  uneqin  3222  trin  3893  pwin  4045  peano5  4347  fin  5107
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