ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  xpmlem Unicode version

Theorem xpmlem 5050
Description: The cross product of inhabited classes is inhabited. (Contributed by Jim Kingdon, 11-Dec-2018.)
Assertion
Ref Expression
xpmlem  |-  ( ( E. x  x  e.  A  /\  E. y 
y  e.  B )  <->  E. z  z  e.  ( A  X.  B
) )
Distinct variable groups:    x, y, z, A    x, B, y, z

Proof of Theorem xpmlem
StepHypRef Expression
1 eeanv 1932 . . 3  |-  ( E. x E. y ( x  e.  A  /\  y  e.  B )  <->  ( E. x  x  e.  A  /\  E. y 
y  e.  B ) )
2 vex 2741 . . . . . 6  |-  x  e. 
_V
3 vex 2741 . . . . . 6  |-  y  e. 
_V
42, 3opex 4230 . . . . 5  |-  <. x ,  y >.  e.  _V
5 eleq1 2240 . . . . . 6  |-  ( z  =  <. x ,  y
>.  ->  ( z  e.  ( A  X.  B
)  <->  <. x ,  y
>.  e.  ( A  X.  B ) ) )
6 opelxp 4657 . . . . . 6  |-  ( <.
x ,  y >.  e.  ( A  X.  B
)  <->  ( x  e.  A  /\  y  e.  B ) )
75, 6bitrdi 196 . . . . 5  |-  ( z  =  <. x ,  y
>.  ->  ( z  e.  ( A  X.  B
)  <->  ( x  e.  A  /\  y  e.  B ) ) )
84, 7spcev 2833 . . . 4  |-  ( ( x  e.  A  /\  y  e.  B )  ->  E. z  z  e.  ( A  X.  B
) )
98exlimivv 1896 . . 3  |-  ( E. x E. y ( x  e.  A  /\  y  e.  B )  ->  E. z  z  e.  ( A  X.  B
) )
101, 9sylbir 135 . 2  |-  ( ( E. x  x  e.  A  /\  E. y 
y  e.  B )  ->  E. z  z  e.  ( A  X.  B
) )
11 elxp 4644 . . . . 5  |-  ( z  e.  ( A  X.  B )  <->  E. x E. y ( z  = 
<. x ,  y >.  /\  ( x  e.  A  /\  y  e.  B
) ) )
12 simpr 110 . . . . . 6  |-  ( ( z  =  <. x ,  y >.  /\  (
x  e.  A  /\  y  e.  B )
)  ->  ( x  e.  A  /\  y  e.  B ) )
13122eximi 1601 . . . . 5  |-  ( E. x E. y ( z  =  <. x ,  y >.  /\  (
x  e.  A  /\  y  e.  B )
)  ->  E. x E. y ( x  e.  A  /\  y  e.  B ) )
1411, 13sylbi 121 . . . 4  |-  ( z  e.  ( A  X.  B )  ->  E. x E. y ( x  e.  A  /\  y  e.  B ) )
1514exlimiv 1598 . . 3  |-  ( E. z  z  e.  ( A  X.  B )  ->  E. x E. y
( x  e.  A  /\  y  e.  B
) )
1615, 1sylib 122 . 2  |-  ( E. z  z  e.  ( A  X.  B )  ->  ( E. x  x  e.  A  /\  E. y  y  e.  B
) )
1710, 16impbii 126 1  |-  ( ( E. x  x  e.  A  /\  E. y 
y  e.  B )  <->  E. z  z  e.  ( A  X.  B
) )
Colors of variables: wff set class
Syntax hints:    /\ wa 104    <-> wb 105    = wceq 1353   E.wex 1492    e. wcel 2148   <.cop 3596    X. cxp 4625
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-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-14 2151  ax-ext 2159  ax-sep 4122  ax-pow 4175  ax-pr 4210
This theorem depends on definitions:  df-bi 117  df-3an 980  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ral 2460  df-rex 2461  df-v 2740  df-un 3134  df-in 3136  df-ss 3143  df-pw 3578  df-sn 3599  df-pr 3600  df-op 3602  df-opab 4066  df-xp 4633
This theorem is referenced by:  xpm  5051
  Copyright terms: Public domain W3C validator