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Theorem bj-inex 13942
Description: The intersection of two sets is a set, from bounded separation. (Contributed by BJ, 19-Nov-2019.) (Proof modification is discouraged.)
Assertion
Ref Expression
bj-inex  |-  ( ( A  e.  V  /\  B  e.  W )  ->  ( A  i^i  B
)  e.  _V )

Proof of Theorem bj-inex
Dummy variables  x  y  z are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 elisset 2744 . 2  |-  ( A  e.  V  ->  E. x  x  =  A )
2 elisset 2744 . 2  |-  ( B  e.  W  ->  E. y 
y  =  B )
3 ax-17 1519 . . . 4  |-  ( E. y  y  =  B  ->  A. x E. y 
y  =  B )
4 19.29r 1614 . . . 4  |-  ( ( E. x  x  =  A  /\  A. x E. y  y  =  B )  ->  E. x
( x  =  A  /\  E. y  y  =  B ) )
53, 4sylan2 284 . . 3  |-  ( ( E. x  x  =  A  /\  E. y 
y  =  B )  ->  E. x ( x  =  A  /\  E. y  y  =  B
) )
6 ax-17 1519 . . . . 5  |-  ( x  =  A  ->  A. y  x  =  A )
7 19.29 1613 . . . . 5  |-  ( ( A. y  x  =  A  /\  E. y 
y  =  B )  ->  E. y ( x  =  A  /\  y  =  B ) )
86, 7sylan 281 . . . 4  |-  ( ( x  =  A  /\  E. y  y  =  B )  ->  E. y
( x  =  A  /\  y  =  B ) )
98eximi 1593 . . 3  |-  ( E. x ( x  =  A  /\  E. y 
y  =  B )  ->  E. x E. y
( x  =  A  /\  y  =  B ) )
10 ineq12 3323 . . . . 5  |-  ( ( x  =  A  /\  y  =  B )  ->  ( x  i^i  y
)  =  ( A  i^i  B ) )
11102eximi 1594 . . . 4  |-  ( E. x E. y ( x  =  A  /\  y  =  B )  ->  E. x E. y
( x  i^i  y
)  =  ( A  i^i  B ) )
12 dfin5 3128 . . . . . . 7  |-  ( x  i^i  y )  =  { z  e.  x  |  z  e.  y }
13 vex 2733 . . . . . . . 8  |-  x  e. 
_V
14 ax-bdel 13856 . . . . . . . . 9  |- BOUNDED  z  e.  y
15 bdcv 13883 . . . . . . . . 9  |- BOUNDED  x
1614, 15bdrabexg 13941 . . . . . . . 8  |-  ( x  e.  _V  ->  { z  e.  x  |  z  e.  y }  e.  _V )
1713, 16ax-mp 5 . . . . . . 7  |-  { z  e.  x  |  z  e.  y }  e.  _V
1812, 17eqeltri 2243 . . . . . 6  |-  ( x  i^i  y )  e. 
_V
19 eleq1 2233 . . . . . 6  |-  ( ( x  i^i  y )  =  ( A  i^i  B )  ->  ( (
x  i^i  y )  e.  _V  <->  ( A  i^i  B )  e.  _V )
)
2018, 19mpbii 147 . . . . 5  |-  ( ( x  i^i  y )  =  ( A  i^i  B )  ->  ( A  i^i  B )  e.  _V )
2120exlimivv 1889 . . . 4  |-  ( E. x E. y ( x  i^i  y )  =  ( A  i^i  B )  ->  ( A  i^i  B )  e.  _V )
2211, 21syl 14 . . 3  |-  ( E. x E. y ( x  =  A  /\  y  =  B )  ->  ( A  i^i  B
)  e.  _V )
235, 9, 223syl 17 . 2  |-  ( ( E. x  x  =  A  /\  E. y 
y  =  B )  ->  ( A  i^i  B )  e.  _V )
241, 2, 23syl2an 287 1  |-  ( ( A  e.  V  /\  B  e.  W )  ->  ( A  i^i  B
)  e.  _V )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 103   A.wal 1346    = wceq 1348   E.wex 1485    e. wcel 2141   {crab 2452   _Vcvv 2730    i^i cin 3120
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-io 704  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-10 1498  ax-11 1499  ax-i12 1500  ax-bndl 1502  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152  ax-bd0 13848  ax-bdan 13850  ax-bdel 13856  ax-bdsb 13857  ax-bdsep 13919
This theorem depends on definitions:  df-bi 116  df-tru 1351  df-nf 1454  df-sb 1756  df-clab 2157  df-cleq 2163  df-clel 2166  df-nfc 2301  df-rab 2457  df-v 2732  df-in 3127  df-ss 3134  df-bdc 13876
This theorem is referenced by:  speano5  13979
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