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Theorem tfr0dm 6468
Description: Transfinite recursion is defined at the empty set. (Contributed by Jim Kingdon, 8-Mar-2022.)
Hypothesis
Ref Expression
tfr.1  |-  F  = recs ( G )
Assertion
Ref Expression
tfr0dm  |-  ( ( G `  (/) )  e.  V  ->  (/)  e.  dom  F )

Proof of Theorem tfr0dm
Dummy variables  x  f  y are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 0ex 4211 . . . . 5  |-  (/)  e.  _V
2 opexg 4314 . . . . 5  |-  ( (
(/)  e.  _V  /\  ( G `  (/) )  e.  V )  ->  <. (/) ,  ( G `  (/) ) >.  e.  _V )
31, 2mpan 424 . . . 4  |-  ( ( G `  (/) )  e.  V  ->  <. (/) ,  ( G `  (/) ) >.  e.  _V )
4 snidg 3695 . . . 4  |-  ( <. (/)
,  ( G `  (/) ) >.  e.  _V  -> 
<. (/) ,  ( G `
 (/) ) >.  e.  { <.
(/) ,  ( G `  (/) ) >. } )
53, 4syl 14 . . 3  |-  ( ( G `  (/) )  e.  V  ->  <. (/) ,  ( G `  (/) ) >.  e.  { <. (/) ,  ( G `
 (/) ) >. } )
6 fnsng 5368 . . . . 5  |-  ( (
(/)  e.  _V  /\  ( G `  (/) )  e.  V )  ->  { <. (/)
,  ( G `  (/) ) >. }  Fn  { (/)
} )
71, 6mpan 424 . . . 4  |-  ( ( G `  (/) )  e.  V  ->  { <. (/) ,  ( G `  (/) ) >. }  Fn  { (/) } )
8 fvsng 5835 . . . . . . 7  |-  ( (
(/)  e.  _V  /\  ( G `  (/) )  e.  V )  ->  ( { <. (/) ,  ( G `
 (/) ) >. } `  (/) )  =  ( G `
 (/) ) )
91, 8mpan 424 . . . . . 6  |-  ( ( G `  (/) )  e.  V  ->  ( { <.
(/) ,  ( G `  (/) ) >. } `  (/) )  =  ( G `
 (/) ) )
10 res0 5009 . . . . . . 7  |-  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  (/) )  =  (/)
1110fveq2i 5630 . . . . . 6  |-  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  (/) ) )  =  ( G `  (/) )
129, 11eqtr4di 2280 . . . . 5  |-  ( ( G `  (/) )  e.  V  ->  ( { <.
(/) ,  ( G `  (/) ) >. } `  (/) )  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  (/) ) ) )
13 fveq2 5627 . . . . . . 7  |-  ( y  =  (/)  ->  ( {
<. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( { <. (/) ,  ( G `
 (/) ) >. } `  (/) ) )
14 reseq2 5000 . . . . . . . 8  |-  ( y  =  (/)  ->  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
)  =  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  (/) ) )
1514fveq2d 5631 . . . . . . 7  |-  ( y  =  (/)  ->  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  (/) ) ) )
1613, 15eqeq12d 2244 . . . . . 6  |-  ( y  =  (/)  ->  ( ( { <. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) )  <->  ( { <.
(/) ,  ( G `  (/) ) >. } `  (/) )  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  (/) ) ) ) )
171, 16ralsn 3709 . . . . 5  |-  ( A. y  e.  { (/) }  ( { <. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) )  <->  ( { <.
(/) ,  ( G `  (/) ) >. } `  (/) )  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  (/) ) ) )
1812, 17sylibr 134 . . . 4  |-  ( ( G `  (/) )  e.  V  ->  A. y  e.  { (/) }  ( {
<. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) )
19 suc0 4502 . . . . . 6  |-  suc  (/)  =  { (/)
}
20 0elon 4483 . . . . . . 7  |-  (/)  e.  On
2120onsuci 4608 . . . . . 6  |-  suc  (/)  e.  On
2219, 21eqeltrri 2303 . . . . 5  |-  { (/) }  e.  On
23 fneq2 5410 . . . . . . 7  |-  ( x  =  { (/) }  ->  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x 
<->  { <. (/) ,  ( G `
 (/) ) >. }  Fn  {
(/) } ) )
24 raleq 2728 . . . . . . 7  |-  ( x  =  { (/) }  ->  ( A. y  e.  x  ( { <. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) )  <->  A. y  e.  { (/) }  ( {
<. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) ) )
2523, 24anbi12d 473 . . . . . 6  |-  ( x  =  { (/) }  ->  ( ( { <. (/) ,  ( G `  (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) )  <->  ( { <.
(/) ,  ( G `  (/) ) >. }  Fn  {
(/) }  /\  A. y  e.  { (/) }  ( {
<. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) ) ) )
2625rspcev 2907 . . . . 5  |-  ( ( { (/) }  e.  On  /\  ( { <. (/) ,  ( G `  (/) ) >. }  Fn  { (/) }  /\  A. y  e.  { (/) }  ( { <. (/) ,  ( G `  (/) ) >. } `  y )  =  ( G `  ( { <. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) ) )  ->  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) )
2722, 26mpan 424 . . . 4  |-  ( ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  {
(/) }  /\  A. y  e.  { (/) }  ( {
<. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) )  ->  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) )
287, 18, 27syl2anc 411 . . 3  |-  ( ( G `  (/) )  e.  V  ->  E. x  e.  On  ( { <. (/)
,  ( G `  (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/) ,  ( G `
 (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) ) )
29 snexg 4268 . . . . 5  |-  ( <. (/)
,  ( G `  (/) ) >.  e.  _V  ->  { <. (/) ,  ( G `
 (/) ) >. }  e.  _V )
30 eleq2 2293 . . . . . . 7  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( <. (/) ,  ( G `  (/) ) >.  e.  f  <->  <. (/) ,  ( G `
 (/) ) >.  e.  { <.
(/) ,  ( G `  (/) ) >. } ) )
31 fneq1 5409 . . . . . . . . 9  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( f  Fn  x  <->  { <. (/) ,  ( G `
 (/) ) >. }  Fn  x ) )
32 fveq1 5626 . . . . . . . . . . 11  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( f `  y )  =  ( { <. (/) ,  ( G `
 (/) ) >. } `  y ) )
33 reseq1 4999 . . . . . . . . . . . 12  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( f  |`  y )  =  ( { <. (/) ,  ( G `
 (/) ) >. }  |`  y
) )
3433fveq2d 5631 . . . . . . . . . . 11  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( G `  ( f  |`  y
) )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) )
3532, 34eqeq12d 2244 . . . . . . . . . 10  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( ( f `
 y )  =  ( G `  (
f  |`  y ) )  <-> 
( { <. (/) ,  ( G `  (/) ) >. } `  y )  =  ( G `  ( { <. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) ) )
3635ralbidv 2530 . . . . . . . . 9  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( A. y  e.  x  ( f `  y )  =  ( G `  ( f  |`  y ) )  <->  A. y  e.  x  ( { <.
(/) ,  ( G `  (/) ) >. } `  y )  =  ( G `  ( {
<. (/) ,  ( G `
 (/) ) >. }  |`  y
) ) ) )
3731, 36anbi12d 473 . . . . . . . 8  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( ( f  Fn  x  /\  A. y  e.  x  (
f `  y )  =  ( G `  ( f  |`  y
) ) )  <->  ( { <.
(/) ,  ( G `  (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) ) )
3837rexbidv 2531 . . . . . . 7  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y )  =  ( G `  ( f  |`  y ) ) )  <->  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) ) )
3930, 38anbi12d 473 . . . . . 6  |-  ( f  =  { <. (/) ,  ( G `  (/) ) >. }  ->  ( ( <. (/)
,  ( G `  (/) ) >.  e.  f  /\  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y
)  =  ( G `
 ( f  |`  y ) ) ) )  <->  ( <. (/) ,  ( G `  (/) ) >.  e.  { <. (/) ,  ( G `
 (/) ) >. }  /\  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) ) ) )
4039spcegv 2891 . . . . 5  |-  ( {
<. (/) ,  ( G `
 (/) ) >. }  e.  _V  ->  ( ( <. (/)
,  ( G `  (/) ) >.  e.  { <. (/)
,  ( G `  (/) ) >. }  /\  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) )  ->  E. f ( <. (/)
,  ( G `  (/) ) >.  e.  f  /\  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y
)  =  ( G `
 ( f  |`  y ) ) ) ) ) )
413, 29, 403syl 17 . . . 4  |-  ( ( G `  (/) )  e.  V  ->  ( ( <.
(/) ,  ( G `  (/) ) >.  e.  { <.
(/) ,  ( G `  (/) ) >. }  /\  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) )  ->  E. f ( <. (/)
,  ( G `  (/) ) >.  e.  f  /\  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y
)  =  ( G `
 ( f  |`  y ) ) ) ) ) )
42 tfr.1 . . . . . 6  |-  F  = recs ( G )
4342eleq2i 2296 . . . . 5  |-  ( <. (/)
,  ( G `  (/) ) >.  e.  F  <->  <. (/)
,  ( G `  (/) ) >.  e. recs ( G ) )
44 df-recs 6451 . . . . . 6  |- recs ( G )  =  U. {
f  |  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y )  =  ( G `  ( f  |`  y ) ) ) }
4544eleq2i 2296 . . . . 5  |-  ( <. (/)
,  ( G `  (/) ) >.  e. recs ( G )  <->  <. (/) ,  ( G `
 (/) ) >.  e.  U. { f  |  E. x  e.  On  (
f  Fn  x  /\  A. y  e.  x  ( f `  y )  =  ( G `  ( f  |`  y
) ) ) } )
46 eluniab 3900 . . . . 5  |-  ( <. (/)
,  ( G `  (/) ) >.  e.  U. {
f  |  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y )  =  ( G `  ( f  |`  y ) ) ) }  <->  E. f ( <. (/)
,  ( G `  (/) ) >.  e.  f  /\  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y
)  =  ( G `
 ( f  |`  y ) ) ) ) )
4743, 45, 463bitri 206 . . . 4  |-  ( <. (/)
,  ( G `  (/) ) >.  e.  F  <->  E. f ( <. (/) ,  ( G `  (/) ) >.  e.  f  /\  E. x  e.  On  ( f  Fn  x  /\  A. y  e.  x  ( f `  y )  =  ( G `  ( f  |`  y ) ) ) ) )
4841, 47imbitrrdi 162 . . 3  |-  ( ( G `  (/) )  e.  V  ->  ( ( <.
(/) ,  ( G `  (/) ) >.  e.  { <.
(/) ,  ( G `  (/) ) >. }  /\  E. x  e.  On  ( { <. (/) ,  ( G `
 (/) ) >. }  Fn  x  /\  A. y  e.  x  ( { <. (/)
,  ( G `  (/) ) >. } `  y
)  =  ( G `
 ( { <. (/)
,  ( G `  (/) ) >. }  |`  y
) ) ) )  ->  <. (/) ,  ( G `
 (/) ) >.  e.  F
) )
495, 28, 48mp2and 433 . 2  |-  ( ( G `  (/) )  e.  V  ->  <. (/) ,  ( G `  (/) ) >.  e.  F )
50 opeldmg 4928 . . 3  |-  ( (
(/)  e.  _V  /\  ( G `  (/) )  e.  V )  ->  ( <.
(/) ,  ( G `  (/) ) >.  e.  F  -> 
(/)  e.  dom  F ) )
511, 50mpan 424 . 2  |-  ( ( G `  (/) )  e.  V  ->  ( <. (/)
,  ( G `  (/) ) >.  e.  F  -> 
(/)  e.  dom  F ) )
5249, 51mpd 13 1  |-  ( ( G `  (/) )  e.  V  ->  (/)  e.  dom  F )
Colors of variables: wff set class
Syntax hints:    -> wi 4    /\ wa 104    = wceq 1395   E.wex 1538    e. wcel 2200   {cab 2215   A.wral 2508   E.wrex 2509   _Vcvv 2799   (/)c0 3491   {csn 3666   <.cop 3669   U.cuni 3888   Oncon0 4454   suc csuc 4456   dom cdm 4719    |` cres 4721    Fn wfn 5313   ` cfv 5318  recscrecs 6450
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-in1 617  ax-in2 618  ax-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-13 2202  ax-14 2203  ax-ext 2211  ax-sep 4202  ax-nul 4210  ax-pow 4258  ax-pr 4293  ax-un 4524
This theorem depends on definitions:  df-bi 117  df-3an 1004  df-tru 1398  df-fal 1401  df-nf 1507  df-sb 1809  df-eu 2080  df-mo 2081  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-ral 2513  df-rex 2514  df-v 2801  df-sbc 3029  df-dif 3199  df-un 3201  df-in 3203  df-ss 3210  df-nul 3492  df-pw 3651  df-sn 3672  df-pr 3673  df-op 3675  df-uni 3889  df-br 4084  df-opab 4146  df-tr 4183  df-id 4384  df-iord 4457  df-on 4459  df-suc 4462  df-xp 4725  df-rel 4726  df-cnv 4727  df-co 4728  df-dm 4729  df-res 4731  df-iota 5278  df-fun 5320  df-fn 5321  df-fv 5326  df-recs 6451
This theorem is referenced by:  tfr0  6469
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