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Theorem tfrlem9 8393
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 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))}
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 5880 . . 3 (𝐵 ∈ dom recs(𝐹) → (𝐵 ∈ dom recs(𝐹) ↔ ∃𝑧⟨𝐵, 𝑧⟩ ∈ recs(𝐹)))
21ibi 270 . 2 (𝐵 ∈ dom recs(𝐹) → ∃𝑧⟨𝐵, 𝑧⟩ ∈ recs(𝐹))
3 dfrecs3 8380 . . . . . 6 recs(𝐹) = ∪ {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))}
43eleq2i 2852 . . . . 5 (⟨𝐵, 𝑧⟩ ∈ recs(𝐹) ↔ ⟨𝐵, 𝑧⟩ ∈ ∪ {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))})
5 eluniab 4880 . . . . 5 (⟨𝐵, 𝑧⟩ ∈ ∪ {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))} ↔ ∃𝑓(⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))))
64, 5bitri 278 . . . 4 (⟨𝐵, 𝑧⟩ ∈ recs(𝐹) ↔ ∃𝑓(⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))))
7 fnop 6648 . . . . . . . . . . . . . 14 ((𝑓 Fn 𝑥 ∧ ⟨𝐵, 𝑧⟩ ∈ 𝑓) → 𝐵 ∈ 𝑥)
8 rspe 3252 . . . . . . . . . . . . . . . 16 ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦))))
9 tfrlem.1 . . . . . . . . . . . . . . . . . 18 𝐴 = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))}
109eqabri 2902 . . . . . . . . . . . . . . . . 17 (𝑓 ∈ 𝐴 ↔ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦))))
11 elssuni 4898 . . . . . . . . . . . . . . . . . 18 (𝑓 ∈ 𝐴 → 𝑓 ⊆ ∪ 𝐴)
129recsfval 8388 . . . . . . . . . . . . . . . . . 18 recs(𝐹) = ∪ 𝐴
1311, 12sseqtrrdi 3949 . . . . . . . . . . . . . . . . 17 (𝑓 ∈ 𝐴 → 𝑓 ⊆ recs(𝐹))
1410, 13sylbir 238 . . . . . . . . . . . . . . . 16 (∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦))) → 𝑓 ⊆ recs(𝐹))
158, 14syl 18 . . . . . . . . . . . . . . 15 ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → 𝑓 ⊆ recs(𝐹))
16 fveq2 6885 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = 𝐵 → (𝑓‘𝑦) = (𝑓‘𝐵))
17 reseq2 5964 . . . . . . . . . . . . . . . . . . . . 21 (𝑦 = 𝐵 → (𝑓 ↾ 𝑦) = (𝑓 ↾ 𝐵))
1817fveq2d 6889 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = 𝐵 → (𝐹‘(𝑓 ↾ 𝑦)) = (𝐹‘(𝑓 ↾ 𝐵)))
1916, 18eqeq12d 2776 . . . . . . . . . . . . . . . . . . 19 (𝑦 = 𝐵 → ((𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) ↔ (𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵))))
2019rspcv 3572 . . . . . . . . . . . . . . . . . 18 (𝐵 ∈ 𝑥 → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵))))
21 fndm 6642 . . . . . . . . . . . . . . . . . . . . 21 (𝑓 Fn 𝑥 → dom 𝑓 = 𝑥)
2221eleq2d 2846 . . . . . . . . . . . . . . . . . . . 20 (𝑓 Fn 𝑥 → (𝐵 ∈ dom 𝑓 ↔ 𝐵 ∈ 𝑥))
239tfrlem7 8391 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Fun recs(𝐹)
24 funssfv 6906 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ((Fun recs(𝐹) ∧ 𝑓 ⊆ recs(𝐹) ∧ 𝐵 ∈ dom 𝑓) → (recs(𝐹)‘𝐵) = (𝑓‘𝐵))
2523, 24mp3an1 1477 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ((𝑓 ⊆ recs(𝐹) ∧ 𝐵 ∈ dom 𝑓) → (recs(𝐹)‘𝐵) = (𝑓‘𝐵))
2625adantrl 729 . . . . . . . . . . . . . . . . . . . . . . . . . 26 ((𝑓 ⊆ recs(𝐹) ∧ ((𝑓 Fn 𝑥 ∧ 𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓)) → (recs(𝐹)‘𝐵) = (𝑓‘𝐵))
2721eleq1d 2845 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (𝑓 Fn 𝑥 → (dom 𝑓 ∈ On ↔ 𝑥 ∈ On))
28 onelss 6405 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (dom 𝑓 ∈ On → (𝐵 ∈ dom 𝑓 → 𝐵 ⊆ dom 𝑓))
2927, 28biimtrrdi 257 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝐵 ∈ dom 𝑓 → 𝐵 ⊆ dom 𝑓)))
3029imp31 423 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 (((𝑓 Fn 𝑥 ∧ 𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓) → 𝐵 ⊆ dom 𝑓)
31 fun2ssres 6585 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 ((Fun recs(𝐹) ∧ 𝑓 ⊆ recs(𝐹) ∧ 𝐵 ⊆ dom 𝑓) → (recs(𝐹) ↾ 𝐵) = (𝑓 ↾ 𝐵))
3231fveq2d 6889 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ((Fun recs(𝐹) ∧ 𝑓 ⊆ recs(𝐹) ∧ 𝐵 ⊆ dom 𝑓) → (𝐹‘(recs(𝐹) ↾ 𝐵)) = (𝐹‘(𝑓 ↾ 𝐵)))
3323, 32mp3an1 1477 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 ((𝑓 ⊆ recs(𝐹) ∧ 𝐵 ⊆ dom 𝑓) → (𝐹‘(recs(𝐹) ↾ 𝐵)) = (𝐹‘(𝑓 ↾ 𝐵)))
3430, 33sylan2 605 . . . . . . . . . . . . . . . . . . . . . . . . . 26 ((𝑓 ⊆ recs(𝐹) ∧ ((𝑓 Fn 𝑥 ∧ 𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓)) → (𝐹‘(recs(𝐹) ↾ 𝐵)) = (𝐹‘(𝑓 ↾ 𝐵)))
3526, 34eqeq12d 2776 . . . . . . . . . . . . . . . . . . . . . . . . 25 ((𝑓 ⊆ recs(𝐹) ∧ ((𝑓 Fn 𝑥 ∧ 𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓)) → ((recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)) ↔ (𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵))))
3635exbiri 823 . . . . . . . . . . . . . . . . . . . . . . . 24 (𝑓 ⊆ recs(𝐹) → (((𝑓 Fn 𝑥 ∧ 𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓) → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
3736com3l 90 . . . . . . . . . . . . . . . . . . . . . . 23 (((𝑓 Fn 𝑥 ∧ 𝑥 ∈ On) ∧ 𝐵 ∈ dom 𝑓) → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
3837exp31 425 . . . . . . . . . . . . . . . . . . . . . 22 (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝐵 ∈ dom 𝑓 → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
3938com34 92 . . . . . . . . . . . . . . . . . . . . 21 (𝑓 Fn 𝑥 → (𝑥 ∈ On → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (𝐵 ∈ dom 𝑓 → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4039com24 96 . . . . . . . . . . . . . . . . . . . 20 (𝑓 Fn 𝑥 → (𝐵 ∈ dom 𝑓 → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4122, 40sylbird 263 . . . . . . . . . . . . . . . . . . 19 (𝑓 Fn 𝑥 → (𝐵 ∈ 𝑥 → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4241com3l 90 . . . . . . . . . . . . . . . . . 18 (𝐵 ∈ 𝑥 → ((𝑓‘𝐵) = (𝐹‘(𝑓 ↾ 𝐵)) → (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4320, 42syld 48 . . . . . . . . . . . . . . . . 17 (𝐵 ∈ 𝑥 → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (𝑓 Fn 𝑥 → (𝑥 ∈ On → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4443com24 96 . . . . . . . . . . . . . . . 16 (𝐵 ∈ 𝑥 → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
4544imp4d 430 . . . . . . . . . . . . . . 15 (𝐵 ∈ 𝑥 → ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → (𝑓 ⊆ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
4615, 45mpdi 46 . . . . . . . . . . . . . 14 (𝐵 ∈ 𝑥 → ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))
477, 46syl 18 . . . . . . . . . . . . 13 ((𝑓 Fn 𝑥 ∧ ⟨𝐵, 𝑧⟩ ∈ 𝑓) → ((𝑥 ∈ On ∧ (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))
4847exp4d 439 . . . . . . . . . . . 12 ((𝑓 Fn 𝑥 ∧ ⟨𝐵, 𝑧⟩ ∈ 𝑓) → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))))
4948ex 418 . . . . . . . . . . 11 (𝑓 Fn 𝑥 → (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
5049com4r 95 . . . . . . . . . 10 (𝑓 Fn 𝑥 → (𝑓 Fn 𝑥 → (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))))
5150pm2.43i 53 . . . . . . . . 9 (𝑓 Fn 𝑥 → (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))))
5251com3l 90 . . . . . . . 8 (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → (𝑓 Fn 𝑥 → (∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))))
5352imp4a 428 . . . . . . 7 (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (𝑥 ∈ On → ((𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))))
5453rexlimdv 3161 . . . . . 6 (⟨𝐵, 𝑧⟩ ∈ 𝑓 → (∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵))))
5554imp 412 . . . . 5 ((⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
5655exlimiv 1962 . . . 4 (∃𝑓(⟨𝐵, 𝑧⟩ ∈ 𝑓 ∧ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ 𝑦)))) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
576, 56sylbi 220 . . 3 (⟨𝐵, 𝑧⟩ ∈ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
5857exlimiv 1962 . 2 (∃𝑧⟨𝐵, 𝑧⟩ ∈ recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
592, 58syl 18 1 (𝐵 ∈ dom recs(𝐹) → (recs(𝐹)‘𝐵) = (𝐹‘(recs(𝐹) ↾ 𝐵)))
Colors of variables:    wff setvar class
This proof depends on syntax axioms:   → wi 4   ∧ wa 401   ∧ w3a 1103   = wceq 1569  ∃wex 1811   ∈ wcel 2144  {cab 2738  ∀wral 3076  ∃wrex 3086   ⊆ wss 3895  ⟨cop 4589  ∪ cuni 4866  dom cdm 5650   ↾ cres 5652  Oncon0 6362  Fun wfun 6532   Fn wfn 6533  ‘cfv 6538  recscrecs 8378
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1942  ax-6 1999  ax-7 2040  ax-8 2146  ax-9 2154  ax-10 2177  ax-11 2193  ax-12 2212  ax-ext 2732  ax-sep 5248  ax-nul 5259  ax-pr 5390  ax-un 7751
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1572  df-fal 1582  df-ex 1812  df-nf 1816  df-sb 2099  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ne 2956  df-ral 3077  df-rex 3087  df-rab 3413  df-v 3452  df-sbc 3739  df-csb 3847  df-ss 3896  df-pss 4014  df-dif 4047  df-in 4091  df-un 4151  df-nul 4279  df-if 4482  df-pw 4558  df-sn 4584  df-pr 4586  df-op 4590  df-uni 4867  df-iun 4952  df-br 5103  df-opab 5167  df-mpt 5186  df-tr 5212  df-id 5545  df-eprel 5550  df-po 5558  df-so 5559  df-fr 5603  df-we 5605  df-xp 5656  df-rel 5657  df-cnv 5658  df-co 5659  df-dm 5660  df-rn 5661  df-res 5662  df-ima 5663  df-pred 6304  df-ord 6365  df-on 6366  df-iota 6494  df-fun 6540  df-fn 6541  df-f 6542  df-fo 6544  df-fv 6546  df-ov 7423  df-2nd 8002  df-frecs 8299  df-wrecs 8330  df-recs 8379
This theorem is used by:  tfrlem11  8396  tfr2a  8403
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