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Theorem eltg3 18589
Description: Membership in a topology generated by a basis. (Contributed by NM, 15-Jul-2006.) (Proof shortened by Mario Carneiro, 30-Aug-2015.)
Assertion
Ref Expression
eltg3  |-  ( B  e.  V  ->  ( A  e.  ( topGen `  B )  <->  E. x
( x  C_  B  /\  A  =  U. x ) ) )
Distinct variable groups:    x, A    x, B    x, V

Proof of Theorem eltg3
StepHypRef Expression
1 elfvdm 5737 . . . 4  |-  ( A  e.  ( topGen `  B
)  ->  B  e.  dom  topGen )
2 inex1g 4456 . . . 4  |-  ( B  e.  dom  topGen  ->  ( B  i^i  ~P A )  e.  _V )
31, 2syl 16 . . 3  |-  ( A  e.  ( topGen `  B
)  ->  ( B  i^i  ~P A )  e. 
_V )
4 eltg4i 18587 . . 3  |-  ( A  e.  ( topGen `  B
)  ->  A  =  U. ( B  i^i  ~P A ) )
5 inss1 3591 . . . . . . 7  |-  ( B  i^i  ~P A ) 
C_  B
6 sseq1 3398 . . . . . . 7  |-  ( x  =  ( B  i^i  ~P A )  ->  (
x  C_  B  <->  ( B  i^i  ~P A )  C_  B ) )
75, 6mpbiri 233 . . . . . 6  |-  ( x  =  ( B  i^i  ~P A )  ->  x  C_  B )
87biantrurd 508 . . . . 5  |-  ( x  =  ( B  i^i  ~P A )  ->  ( A  =  U. x  <->  ( x  C_  B  /\  A  =  U. x
) ) )
9 unieq 4120 . . . . . 6  |-  ( x  =  ( B  i^i  ~P A )  ->  U. x  =  U. ( B  i^i  ~P A ) )
109eqeq2d 2454 . . . . 5  |-  ( x  =  ( B  i^i  ~P A )  ->  ( A  =  U. x  <->  A  =  U. ( B  i^i  ~P A ) ) )
118, 10bitr3d 255 . . . 4  |-  ( x  =  ( B  i^i  ~P A )  ->  (
( x  C_  B  /\  A  =  U. x )  <->  A  =  U. ( B  i^i  ~P A ) ) )
1211spcegv 3079 . . 3  |-  ( ( B  i^i  ~P A
)  e.  _V  ->  ( A  =  U. ( B  i^i  ~P A )  ->  E. x ( x 
C_  B  /\  A  =  U. x ) ) )
133, 4, 12sylc 60 . 2  |-  ( A  e.  ( topGen `  B
)  ->  E. x
( x  C_  B  /\  A  =  U. x ) )
14 eltg3i 18588 . . . . 5  |-  ( ( B  e.  V  /\  x  C_  B )  ->  U. x  e.  ( topGen `
 B ) )
15 eleq1 2503 . . . . 5  |-  ( A  =  U. x  -> 
( A  e.  (
topGen `  B )  <->  U. x  e.  ( topGen `  B )
) )
1614, 15syl5ibrcom 222 . . . 4  |-  ( ( B  e.  V  /\  x  C_  B )  -> 
( A  =  U. x  ->  A  e.  (
topGen `  B ) ) )
1716expimpd 603 . . 3  |-  ( B  e.  V  ->  (
( x  C_  B  /\  A  =  U. x )  ->  A  e.  ( topGen `  B )
) )
1817exlimdv 1690 . 2  |-  ( B  e.  V  ->  ( E. x ( x  C_  B  /\  A  =  U. x )  ->  A  e.  ( topGen `  B )
) )
1913, 18impbid2 204 1  |-  ( B  e.  V  ->  ( A  e.  ( topGen `  B )  <->  E. x
( x  C_  B  /\  A  =  U. x ) ) )
Colors of variables: wff setvar class
Syntax hints:    -> wi 4    <-> wb 184    /\ wa 369    = wceq 1369   E.wex 1586    e. wcel 1756   _Vcvv 2993    i^i cin 3348    C_ wss 3349   ~Pcpw 3881   U.cuni 4112   dom cdm 4861   ` cfv 5439   topGenctg 14397
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1591  ax-4 1602  ax-5 1670  ax-6 1708  ax-7 1728  ax-8 1758  ax-9 1760  ax-10 1775  ax-11 1780  ax-12 1792  ax-13 1943  ax-ext 2423  ax-sep 4434  ax-nul 4442  ax-pow 4491  ax-pr 4552  ax-un 6393
This theorem depends on definitions:  df-bi 185  df-or 370  df-an 371  df-3an 967  df-tru 1372  df-ex 1587  df-nf 1590  df-sb 1701  df-eu 2257  df-mo 2258  df-clab 2430  df-cleq 2436  df-clel 2439  df-nfc 2577  df-ne 2622  df-ral 2741  df-rex 2742  df-rab 2745  df-v 2995  df-sbc 3208  df-dif 3352  df-un 3354  df-in 3356  df-ss 3363  df-nul 3659  df-if 3813  df-pw 3883  df-sn 3899  df-pr 3901  df-op 3905  df-uni 4113  df-br 4314  df-opab 4372  df-mpt 4373  df-id 4657  df-xp 4867  df-rel 4868  df-cnv 4869  df-co 4870  df-dm 4871  df-iota 5402  df-fun 5441  df-fv 5447  df-topgen 14403
This theorem is referenced by:  tgval3  18590  tgtop  18600  eltop3  18603  tgidm  18607  bastop1  18620  tgrest  18785  tgcn  18878  txbasval  19201  opnmblALT  21105  mbfimaopnlem  21155  isfne3  28570  fneuni  28574
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