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Theorem tfrlem9 8353
Description: Lemma for transfinite recursion. Here we compute the value of recs (the union of all acceptable functions). (Contributed by NM, 17-Aug-1994.)
Hypothesis
Ref Expression
tfrlem.1 𝐴 = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))}
Assertion
Ref Expression
tfrlem9 (𝐵 ∈ dom recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
Distinct variable groups:   𝑥,𝑓,𝑦,𝐵   𝑓,𝐹,𝑥,𝑦
Allowed substitution hints:   𝐴(𝑥,𝑦,𝑓)

Proof of Theorem tfrlem9
Dummy variable 𝑧 is distinct from all other variables.
StepHypRef Expression
1 eldm2g 5863 . . 3 (𝐵 ∈ dom recs(𝐹) → (𝐵 ∈ dom recs(𝐹) ↔ ∃𝑧𝐵, 𝑧⟩ ∈ recs(𝐹)))
21ibi 267 . 2 (𝐵 ∈ dom recs(𝐹) → ∃𝑧𝐵, 𝑧⟩ ∈ recs(𝐹))
3 dfrecs3 8341 . . . . . 6 recs(𝐹) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))}
43eleq2i 2820 . . . . 5 (⟨𝐵, 𝑧⟩ ∈ recs(𝐹) ↔ ⟨𝐵, 𝑧⟩ ∈ {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))})
5 eluniab 4885 . . . . 5 (⟨𝐵, 𝑧⟩ ∈ {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))} ↔ ∃𝑓(⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))))
64, 5bitri 275 . . . 4 (⟨𝐵, 𝑧⟩ ∈ recs(𝐹) ↔ ∃𝑓(⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))))
7 fnop 6627 . . . . . . . . . . . . . 14 ((𝑓 Fn 𝑥 ∧ ⟨𝐵, 𝑧⟩ ∈ 𝑓) → 𝐵𝑥)
8 rspe 3227 . . . . . . . . . . . . . . . 16 ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦))))
9 tfrlem.1 . . . . . . . . . . . . . . . . . 18 𝐴 = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))}
109eqabri 2871 . . . . . . . . . . . . . . . . 17 (𝑓𝐴 ↔ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦))))
11 elssuni 4901 . . . . . . . . . . . . . . . . . 18 (𝑓𝐴𝑓 𝐴)
129recsfval 8349 . . . . . . . . . . . . . . . . . 18 recs(𝐹) = 𝐴
1311, 12sseqtrrdi 3988 . . . . . . . . . . . . . . . . 17 (𝑓𝐴𝑓 ⊆ recs(𝐹))
1410, 13sylbir 235 . . . . . . . . . . . . . . . 16 (∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦))) → 𝑓 ⊆ recs(𝐹))
158, 14syl 17 . . . . . . . . . . . . . . 15 ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → 𝑓 ⊆ recs(𝐹))
16 fveq2 6858 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = 𝐵 → (𝑓𝑦) = (𝑓𝐵))
17 reseq2 5945 . . . . . . . . . . . . . . . . . . . . 21 (𝑦 = 𝐵 → (𝑓𝑦) = (𝑓𝐵))
1817fveq2d 6862 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = 𝐵 → (𝐹‘(𝑓𝑦)) = (𝐹‘(𝑓𝐵)))
1916, 18eqeq12d 2745 . . . . . . . . . . . . . . . . . . 19 (𝑦 = 𝐵 → ((𝑓𝑦) = (𝐹‘(𝑓𝑦)) ↔ (𝑓𝐵) = (𝐹‘(𝑓𝐵))))
2019rspcv 3584 . . . . . . . . . . . . . . . . . 18 (𝐵𝑥 → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (𝑓𝐵) = (𝐹‘(𝑓𝐵))))
21 fndm 6621 . . . . . . . . . . . . . . . . . . . . 21 (𝑓 Fn 𝑥 → dom 𝑓 = 𝑥)
2221eleq2d 2814 . . . . . . . . . . . . . . . . . . . 20 (𝑓 Fn 𝑥 → (𝐵 ∈ dom 𝑓𝐵𝑥))
239tfrlem7 8351 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Fun recs(𝐹)
24 funssfv 6879 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ((Fun recs(𝐹) ∧ 𝑓 ⊆ recs(𝐹) ∧ 𝐵 ∈ dom 𝑓) → (recs(𝐹)‘𝐵) = (𝑓𝐵))
2523, 24mp3an1 1450 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ((𝑓 ⊆ recs(𝐹) ∧ 𝐵 ∈ dom 𝑓) → (recs(𝐹)‘𝐵) = (𝑓𝐵))
2625adantrl 716 . . . . . . . . . . . . . . . . . . . . . . . . . 26 ((𝑓 ⊆ recs(𝐹) ∧ ((𝑓 Fn 𝑥𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓)) → (recs(𝐹)‘𝐵) = (𝑓𝐵))
2721eleq1d 2813 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (𝑓 Fn 𝑥 → (dom 𝑓 ∈ On ↔ 𝑥 ∈ On))
28 onelss 6374 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (dom 𝑓 ∈ On → (𝐵 ∈ dom 𝑓𝐵 ⊆ dom 𝑓))
2927, 28biimtrrdi 254 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝐵 ∈ dom 𝑓𝐵 ⊆ dom 𝑓)))
3029imp31 417 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 (((𝑓 Fn 𝑥𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓) → 𝐵 ⊆ dom 𝑓)
31 fun2ssres 6561 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 ((Fun recs(𝐹) ∧ 𝑓 ⊆ recs(𝐹) ∧ 𝐵 ⊆ dom 𝑓) → (recs(𝐹) ↾ 𝐵) = (𝑓𝐵))
3231fveq2d 6862 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ((Fun recs(𝐹) ∧ 𝑓 ⊆ recs(𝐹) ∧ 𝐵 ⊆ dom 𝑓) → (𝐹‘(recs(𝐹) ↾ 𝐵)) = (𝐹‘(𝑓𝐵)))
3323, 32mp3an1 1450 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ((𝑓 ⊆ recs(𝐹) ∧ 𝐵 ⊆ dom 𝑓) → (𝐹‘(recs(𝐹) ↾ 𝐵)) = (𝐹‘(𝑓𝐵)))
3430, 33sylan2 593 . . . . . . . . . . . . . . . . . . . . . . . . . 26 ((𝑓 ⊆ recs(𝐹) ∧ ((𝑓 Fn 𝑥𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓)) → (𝐹‘(recs(𝐹) ↾ 𝐵)) = (𝐹‘(𝑓𝐵)))
3526, 34eqeq12d 2745 . . . . . . . . . . . . . . . . . . . . . . . . 25 ((𝑓 ⊆ recs(𝐹) ∧ ((𝑓 Fn 𝑥𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓)) → ((recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)) ↔ (𝑓𝐵) = (𝐹‘(𝑓𝐵))))
3635exbiri 810 . . . . . . . . . . . . . . . . . . . . . . . 24 (𝑓 ⊆ recs(𝐹) → (((𝑓 Fn 𝑥𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓) → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
3736com3l 89 . . . . . . . . . . . . . . . . . . . . . . 23 (((𝑓 Fn 𝑥𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓) → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
3837exp31 419 . . . . . . . . . . . . . . . . . . . . . 22 (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝐵 ∈ dom 𝑓 → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
3938com34 91 . . . . . . . . . . . . . . . . . . . . 21 (𝑓 Fn 𝑥 → (𝑥 ∈ On → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (𝐵 ∈ dom 𝑓 → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4039com24 95 . . . . . . . . . . . . . . . . . . . 20 (𝑓 Fn 𝑥 → (𝐵 ∈ dom 𝑓 → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4122, 40sylbird 260 . . . . . . . . . . . . . . . . . . 19 (𝑓 Fn 𝑥 → (𝐵𝑥 → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4241com3l 89 . . . . . . . . . . . . . . . . . 18 (𝐵𝑥 → ((𝑓𝐵) = (𝐹‘(𝑓𝐵)) → (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4320, 42syld 47 . . . . . . . . . . . . . . . . 17 (𝐵𝑥 → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4443com24 95 . . . . . . . . . . . . . . . 16 (𝐵𝑥 → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4544imp4d 424 . . . . . . . . . . . . . . 15 (𝐵𝑥 → ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
4615, 45mpdi 45 . . . . . . . . . . . . . 14 (𝐵𝑥 → ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))
477, 46syl 17 . . . . . . . . . . . . 13 ((𝑓 Fn 𝑥 ∧ ⟨𝐵, 𝑧⟩ ∈ 𝑓) → ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))
4847exp4d 433 . . . . . . . . . . . 12 ((𝑓 Fn 𝑥 ∧ ⟨𝐵, 𝑧⟩ ∈ 𝑓) → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))))
4948ex 412 . . . . . . . . . . 11 (𝑓 Fn 𝑥 → (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
5049com4r 94 . . . . . . . . . 10 (𝑓 Fn 𝑥 → (𝑓 Fn 𝑥 → (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
5150pm2.43i 52 . . . . . . . . 9 (𝑓 Fn 𝑥 → (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))))
5251com3l 89 . . . . . . . 8 (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))))
5352imp4a 422 . . . . . . 7 (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → ((𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
5453rexlimdv 3132 . . . . . 6 (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))
5554imp 406 . . . . 5 ((⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
5655exlimiv 1930 . . . 4 (∃𝑓(⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
576, 56sylbi 217 . . 3 (⟨𝐵, 𝑧⟩ ∈ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
5857exlimiv 1930 . 2 (∃𝑧𝐵, 𝑧⟩ ∈ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
592, 58syl 17 1 (𝐵 ∈ dom recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 395  w3a 1086   = wceq 1540  wex 1779  wcel 2109  {cab 2707  wral 3044  wrex 3053  wss 3914  cop 4595   cuni 4871  dom cdm 5638  cres 5640  Oncon0 6332  Fun wfun 6505   Fn wfn 6506  cfv 6511  recscrecs 8339
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-10 2142  ax-11 2158  ax-12 2178  ax-ext 2701  ax-sep 5251  ax-nul 5261  ax-pr 5387  ax-un 7711
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-nf 1784  df-sb 2066  df-mo 2533  df-eu 2562  df-clab 2708  df-cleq 2721  df-clel 2803  df-nfc 2878  df-ne 2926  df-ral 3045  df-rex 3054  df-rab 3406  df-v 3449  df-sbc 3754  df-csb 3863  df-dif 3917  df-un 3919  df-in 3921  df-ss 3931  df-pss 3934  df-nul 4297  df-if 4489  df-pw 4565  df-sn 4590  df-pr 4592  df-op 4596  df-uni 4872  df-iun 4957  df-br 5108  df-opab 5170  df-mpt 5189  df-tr 5215  df-id 5533  df-eprel 5538  df-po 5546  df-so 5547  df-fr 5591  df-we 5593  df-xp 5644  df-rel 5645  df-cnv 5646  df-co 5647  df-dm 5648  df-rn 5649  df-res 5650  df-ima 5651  df-pred 6274  df-ord 6335  df-on 6336  df-iota 6464  df-fun 6513  df-fn 6514  df-f 6515  df-fo 6517  df-fv 6519  df-ov 7390  df-2nd 7969  df-frecs 8260  df-wrecs 8291  df-recs 8340
This theorem is referenced by:  tfrlem11  8356  tfr2a  8363
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