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Theorem dfrdg2 33771
Description: Alternate definition of the recursive function generator when 𝐼 is a set. (Contributed by Scott Fenton, 26-Mar-2014.) (Revised by Mario Carneiro, 19-Apr-2014.)
Assertion
Ref Expression
dfrdg2 (𝐼𝑉 → rec(𝐹, 𝐼) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))})
Distinct variable groups:   𝑓,𝐹,𝑥,𝑦   𝑓,𝐼,𝑥,𝑦
Allowed substitution hints:   𝑉(𝑥,𝑦,𝑓)

Proof of Theorem dfrdg2
Dummy variables 𝑔 𝑖 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 rdgeq2 8243 . . 3 (𝑖 = 𝐼 → rec(𝐹, 𝑖) = rec(𝐹, 𝐼))
2 ifeq1 4463 . . . . . . . . 9 (𝑖 = 𝐼 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
32eqeq2d 2749 . . . . . . . 8 (𝑖 = 𝐼 → ((𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) ↔ (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
43ralbidv 3112 . . . . . . 7 (𝑖 = 𝐼 → (∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) ↔ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
54anbi2d 629 . . . . . 6 (𝑖 = 𝐼 → ((𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))) ↔ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))))
65rexbidv 3226 . . . . 5 (𝑖 = 𝐼 → (∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))) ↔ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))))
76abbidv 2807 . . . 4 (𝑖 = 𝐼 → {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))} = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))})
87unieqd 4853 . . 3 (𝑖 = 𝐼 {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))} = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))})
91, 8eqeq12d 2754 . 2 (𝑖 = 𝐼 → (rec(𝐹, 𝑖) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))} ↔ rec(𝐹, 𝐼) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))}))
10 df-rdg 8241 . . 3 rec(𝐹, 𝑖) = recs((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔))))))
11 dfrecs3 8203 . . 3 recs((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)))}
12 vex 3436 . . . . . . . . . . . . 13 𝑓 ∈ V
1312resex 5939 . . . . . . . . . . . 12 (𝑓𝑦) ∈ V
14 eqeq1 2742 . . . . . . . . . . . . . . 15 (𝑔 = (𝑓𝑦) → (𝑔 = ∅ ↔ (𝑓𝑦) = ∅))
15 relres 5920 . . . . . . . . . . . . . . . 16 Rel (𝑓𝑦)
16 reldm0 5837 . . . . . . . . . . . . . . . 16 (Rel (𝑓𝑦) → ((𝑓𝑦) = ∅ ↔ dom (𝑓𝑦) = ∅))
1715, 16ax-mp 5 . . . . . . . . . . . . . . 15 ((𝑓𝑦) = ∅ ↔ dom (𝑓𝑦) = ∅)
1814, 17bitrdi 287 . . . . . . . . . . . . . 14 (𝑔 = (𝑓𝑦) → (𝑔 = ∅ ↔ dom (𝑓𝑦) = ∅))
19 dmeq 5812 . . . . . . . . . . . . . . . 16 (𝑔 = (𝑓𝑦) → dom 𝑔 = dom (𝑓𝑦))
20 limeq 6278 . . . . . . . . . . . . . . . 16 (dom 𝑔 = dom (𝑓𝑦) → (Lim dom 𝑔 ↔ Lim dom (𝑓𝑦)))
2119, 20syl 17 . . . . . . . . . . . . . . 15 (𝑔 = (𝑓𝑦) → (Lim dom 𝑔 ↔ Lim dom (𝑓𝑦)))
22 rneq 5845 . . . . . . . . . . . . . . . . 17 (𝑔 = (𝑓𝑦) → ran 𝑔 = ran (𝑓𝑦))
23 df-ima 5602 . . . . . . . . . . . . . . . . 17 (𝑓𝑦) = ran (𝑓𝑦)
2422, 23eqtr4di 2796 . . . . . . . . . . . . . . . 16 (𝑔 = (𝑓𝑦) → ran 𝑔 = (𝑓𝑦))
2524unieqd 4853 . . . . . . . . . . . . . . 15 (𝑔 = (𝑓𝑦) → ran 𝑔 = (𝑓𝑦))
26 id 22 . . . . . . . . . . . . . . . . 17 (𝑔 = (𝑓𝑦) → 𝑔 = (𝑓𝑦))
2719unieqd 4853 . . . . . . . . . . . . . . . . 17 (𝑔 = (𝑓𝑦) → dom 𝑔 = dom (𝑓𝑦))
2826, 27fveq12d 6781 . . . . . . . . . . . . . . . 16 (𝑔 = (𝑓𝑦) → (𝑔 dom 𝑔) = ((𝑓𝑦)‘ dom (𝑓𝑦)))
2928fveq2d 6778 . . . . . . . . . . . . . . 15 (𝑔 = (𝑓𝑦) → (𝐹‘(𝑔 dom 𝑔)) = (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))
3021, 25, 29ifbieq12d 4487 . . . . . . . . . . . . . 14 (𝑔 = (𝑓𝑦) → if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔))) = if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦)))))
3118, 30ifbieq2d 4485 . . . . . . . . . . . . 13 (𝑔 = (𝑓𝑦) → if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))) = if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))))
32 eqid 2738 . . . . . . . . . . . . 13 (𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔))))) = (𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))
33 vex 3436 . . . . . . . . . . . . . 14 𝑖 ∈ V
34 imaexg 7762 . . . . . . . . . . . . . . . . 17 (𝑓 ∈ V → (𝑓𝑦) ∈ V)
3512, 34ax-mp 5 . . . . . . . . . . . . . . . 16 (𝑓𝑦) ∈ V
3635uniex 7594 . . . . . . . . . . . . . . 15 (𝑓𝑦) ∈ V
37 fvex 6787 . . . . . . . . . . . . . . 15 (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))) ∈ V
3836, 37ifex 4509 . . . . . . . . . . . . . 14 if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦)))) ∈ V
3933, 38ifex 4509 . . . . . . . . . . . . 13 if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))) ∈ V
4031, 32, 39fvmpt 6875 . . . . . . . . . . . 12 ((𝑓𝑦) ∈ V → ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)) = if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))))
4113, 40ax-mp 5 . . . . . . . . . . 11 ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)) = if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦)))))
42 dmres 5913 . . . . . . . . . . . . 13 dom (𝑓𝑦) = (𝑦 ∩ dom 𝑓)
43 onelss 6308 . . . . . . . . . . . . . . . . 17 (𝑥 ∈ On → (𝑦𝑥𝑦𝑥))
4443imp 407 . . . . . . . . . . . . . . . 16 ((𝑥 ∈ On ∧ 𝑦𝑥) → 𝑦𝑥)
45443adant2 1130 . . . . . . . . . . . . . . 15 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → 𝑦𝑥)
46 fndm 6536 . . . . . . . . . . . . . . . 16 (𝑓 Fn 𝑥 → dom 𝑓 = 𝑥)
47463ad2ant2 1133 . . . . . . . . . . . . . . 15 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → dom 𝑓 = 𝑥)
4845, 47sseqtrrd 3962 . . . . . . . . . . . . . 14 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → 𝑦 ⊆ dom 𝑓)
49 df-ss 3904 . . . . . . . . . . . . . 14 (𝑦 ⊆ dom 𝑓 ↔ (𝑦 ∩ dom 𝑓) = 𝑦)
5048, 49sylib 217 . . . . . . . . . . . . 13 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → (𝑦 ∩ dom 𝑓) = 𝑦)
5142, 50eqtrid 2790 . . . . . . . . . . . 12 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → dom (𝑓𝑦) = 𝑦)
52 eqeq1 2742 . . . . . . . . . . . . . 14 (dom (𝑓𝑦) = 𝑦 → (dom (𝑓𝑦) = ∅ ↔ 𝑦 = ∅))
53 limeq 6278 . . . . . . . . . . . . . . 15 (dom (𝑓𝑦) = 𝑦 → (Lim dom (𝑓𝑦) ↔ Lim 𝑦))
54 unieq 4850 . . . . . . . . . . . . . . . . 17 (dom (𝑓𝑦) = 𝑦 dom (𝑓𝑦) = 𝑦)
5554fveq2d 6778 . . . . . . . . . . . . . . . 16 (dom (𝑓𝑦) = 𝑦 → ((𝑓𝑦)‘ dom (𝑓𝑦)) = ((𝑓𝑦)‘ 𝑦))
5655fveq2d 6778 . . . . . . . . . . . . . . 15 (dom (𝑓𝑦) = 𝑦 → (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))) = (𝐹‘((𝑓𝑦)‘ 𝑦)))
5753, 56ifbieq2d 4485 . . . . . . . . . . . . . 14 (dom (𝑓𝑦) = 𝑦 → if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦)))) = if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦))))
5852, 57ifbieq2d 4485 . . . . . . . . . . . . 13 (dom (𝑓𝑦) = 𝑦 → if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))))
59 onelon 6291 . . . . . . . . . . . . . . . 16 ((𝑥 ∈ On ∧ 𝑦𝑥) → 𝑦 ∈ On)
60 eloni 6276 . . . . . . . . . . . . . . . 16 (𝑦 ∈ On → Ord 𝑦)
6159, 60syl 17 . . . . . . . . . . . . . . 15 ((𝑥 ∈ On ∧ 𝑦𝑥) → Ord 𝑦)
62613adant2 1130 . . . . . . . . . . . . . 14 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → Ord 𝑦)
63 ordzsl 7692 . . . . . . . . . . . . . . 15 (Ord 𝑦 ↔ (𝑦 = ∅ ∨ ∃𝑧 ∈ On 𝑦 = suc 𝑧 ∨ Lim 𝑦))
64 iftrue 4465 . . . . . . . . . . . . . . . . 17 (𝑦 = ∅ → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = 𝑖)
65 iftrue 4465 . . . . . . . . . . . . . . . . 17 (𝑦 = ∅ → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) = 𝑖)
6664, 65eqtr4d 2781 . . . . . . . . . . . . . . . 16 (𝑦 = ∅ → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
67 vex 3436 . . . . . . . . . . . . . . . . . . . . . . 23 𝑧 ∈ V
6867sucid 6345 . . . . . . . . . . . . . . . . . . . . . 22 𝑧 ∈ suc 𝑧
69 fvres 6793 . . . . . . . . . . . . . . . . . . . . . 22 (𝑧 ∈ suc 𝑧 → ((𝑓 ↾ suc 𝑧)‘𝑧) = (𝑓𝑧))
7068, 69ax-mp 5 . . . . . . . . . . . . . . . . . . . . 21 ((𝑓 ↾ suc 𝑧)‘𝑧) = (𝑓𝑧)
71 eloni 6276 . . . . . . . . . . . . . . . . . . . . . . 23 (𝑧 ∈ On → Ord 𝑧)
72 ordunisuc 7679 . . . . . . . . . . . . . . . . . . . . . . 23 (Ord 𝑧 suc 𝑧 = 𝑧)
7371, 72syl 17 . . . . . . . . . . . . . . . . . . . . . 22 (𝑧 ∈ On → suc 𝑧 = 𝑧)
7473fveq2d 6778 . . . . . . . . . . . . . . . . . . . . 21 (𝑧 ∈ On → ((𝑓 ↾ suc 𝑧)‘ suc 𝑧) = ((𝑓 ↾ suc 𝑧)‘𝑧))
7573fveq2d 6778 . . . . . . . . . . . . . . . . . . . . 21 (𝑧 ∈ On → (𝑓 suc 𝑧) = (𝑓𝑧))
7670, 74, 753eqtr4a 2804 . . . . . . . . . . . . . . . . . . . 20 (𝑧 ∈ On → ((𝑓 ↾ suc 𝑧)‘ suc 𝑧) = (𝑓 suc 𝑧))
7776fveq2d 6778 . . . . . . . . . . . . . . . . . . 19 (𝑧 ∈ On → (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)) = (𝐹‘(𝑓 suc 𝑧)))
78 nsuceq0 6346 . . . . . . . . . . . . . . . . . . . . . 22 suc 𝑧 ≠ ∅
7978neii 2945 . . . . . . . . . . . . . . . . . . . . 21 ¬ suc 𝑧 = ∅
8079iffalsei 4469 . . . . . . . . . . . . . . . . . . . 20 if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))) = if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))
81 nlimsucg 7689 . . . . . . . . . . . . . . . . . . . . 21 (𝑧 ∈ V → ¬ Lim suc 𝑧)
82 iffalse 4468 . . . . . . . . . . . . . . . . . . . . 21 (¬ Lim suc 𝑧 → if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧))) = (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))
8367, 81, 82mp2b 10 . . . . . . . . . . . . . . . . . . . 20 if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧))) = (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧))
8480, 83eqtri 2766 . . . . . . . . . . . . . . . . . . 19 if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))) = (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧))
8579iffalsei 4469 . . . . . . . . . . . . . . . . . . . 20 if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧)))) = if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧)))
86 iffalse 4468 . . . . . . . . . . . . . . . . . . . . 21 (¬ Lim suc 𝑧 → if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧))) = (𝐹‘(𝑓 suc 𝑧)))
8767, 81, 86mp2b 10 . . . . . . . . . . . . . . . . . . . 20 if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧))) = (𝐹‘(𝑓 suc 𝑧))
8885, 87eqtri 2766 . . . . . . . . . . . . . . . . . . 19 if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧)))) = (𝐹‘(𝑓 suc 𝑧))
8977, 84, 883eqtr4g 2803 . . . . . . . . . . . . . . . . . 18 (𝑧 ∈ On → if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))) = if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧)))))
90 eqeq1 2742 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = suc 𝑧 → (𝑦 = ∅ ↔ suc 𝑧 = ∅))
91 limeq 6278 . . . . . . . . . . . . . . . . . . . . 21 (𝑦 = suc 𝑧 → (Lim 𝑦 ↔ Lim suc 𝑧))
92 reseq2 5886 . . . . . . . . . . . . . . . . . . . . . . 23 (𝑦 = suc 𝑧 → (𝑓𝑦) = (𝑓 ↾ suc 𝑧))
93 unieq 4850 . . . . . . . . . . . . . . . . . . . . . . 23 (𝑦 = suc 𝑧 𝑦 = suc 𝑧)
9492, 93fveq12d 6781 . . . . . . . . . . . . . . . . . . . . . 22 (𝑦 = suc 𝑧 → ((𝑓𝑦)‘ 𝑦) = ((𝑓 ↾ suc 𝑧)‘ suc 𝑧))
9594fveq2d 6778 . . . . . . . . . . . . . . . . . . . . 21 (𝑦 = suc 𝑧 → (𝐹‘((𝑓𝑦)‘ 𝑦)) = (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))
9691, 95ifbieq2d 4485 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = suc 𝑧 → if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦))) = if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧))))
9790, 96ifbieq2d 4485 . . . . . . . . . . . . . . . . . . 19 (𝑦 = suc 𝑧 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))))
9893fveq2d 6778 . . . . . . . . . . . . . . . . . . . . . 22 (𝑦 = suc 𝑧 → (𝑓 𝑦) = (𝑓 suc 𝑧))
9998fveq2d 6778 . . . . . . . . . . . . . . . . . . . . 21 (𝑦 = suc 𝑧 → (𝐹‘(𝑓 𝑦)) = (𝐹‘(𝑓 suc 𝑧)))
10091, 99ifbieq2d 4485 . . . . . . . . . . . . . . . . . . . 20 (𝑦 = suc 𝑧 → if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))) = if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧))))
10190, 100ifbieq2d 4485 . . . . . . . . . . . . . . . . . . 19 (𝑦 = suc 𝑧 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) = if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧)))))
10297, 101eqeq12d 2754 . . . . . . . . . . . . . . . . . 18 (𝑦 = suc 𝑧 → (if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) ↔ if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘((𝑓 ↾ suc 𝑧)‘ suc 𝑧)))) = if(suc 𝑧 = ∅, 𝑖, if(Lim suc 𝑧, (𝑓𝑦), (𝐹‘(𝑓 suc 𝑧))))))
10389, 102syl5ibrcom 246 . . . . . . . . . . . . . . . . 17 (𝑧 ∈ On → (𝑦 = suc 𝑧 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
104103rexlimiv 3209 . . . . . . . . . . . . . . . 16 (∃𝑧 ∈ On 𝑦 = suc 𝑧 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
105 iftrue 4465 . . . . . . . . . . . . . . . . . 18 (Lim 𝑦 → if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦))) = (𝑓𝑦))
106 df-lim 6271 . . . . . . . . . . . . . . . . . . . . 21 (Lim 𝑦 ↔ (Ord 𝑦𝑦 ≠ ∅ ∧ 𝑦 = 𝑦))
107106simp2bi 1145 . . . . . . . . . . . . . . . . . . . 20 (Lim 𝑦𝑦 ≠ ∅)
108107neneqd 2948 . . . . . . . . . . . . . . . . . . 19 (Lim 𝑦 → ¬ 𝑦 = ∅)
109108iffalsed 4470 . . . . . . . . . . . . . . . . . 18 (Lim 𝑦 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦))))
110 iftrue 4465 . . . . . . . . . . . . . . . . . 18 (Lim 𝑦 → if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))) = (𝑓𝑦))
111105, 109, 1103eqtr4d 2788 . . . . . . . . . . . . . . . . 17 (Lim 𝑦 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))
112108iffalsed 4470 . . . . . . . . . . . . . . . . 17 (Lim 𝑦 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))) = if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))
113111, 112eqtr4d 2781 . . . . . . . . . . . . . . . 16 (Lim 𝑦 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
11466, 104, 1133jaoi 1426 . . . . . . . . . . . . . . 15 ((𝑦 = ∅ ∨ ∃𝑧 ∈ On 𝑦 = suc 𝑧 ∨ Lim 𝑦) → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
11563, 114sylbi 216 . . . . . . . . . . . . . 14 (Ord 𝑦 → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
11662, 115syl 17 . . . . . . . . . . . . 13 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ 𝑦)))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
11758, 116sylan9eqr 2800 . . . . . . . . . . . 12 (((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) ∧ dom (𝑓𝑦) = 𝑦) → if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
11851, 117mpdan 684 . . . . . . . . . . 11 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → if(dom (𝑓𝑦) = ∅, 𝑖, if(Lim dom (𝑓𝑦), (𝑓𝑦), (𝐹‘((𝑓𝑦)‘ dom (𝑓𝑦))))) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
11941, 118eqtrid 2790 . . . . . . . . . 10 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))
120119eqeq2d 2749 . . . . . . . . 9 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥𝑦𝑥) → ((𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)) ↔ (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
1211203expa 1117 . . . . . . . 8 (((𝑥 ∈ On ∧ 𝑓 Fn 𝑥) ∧ 𝑦𝑥) → ((𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)) ↔ (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
122121ralbidva 3111 . . . . . . 7 ((𝑥 ∈ On ∧ 𝑓 Fn 𝑥) → (∀𝑦𝑥 (𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)) ↔ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
123122pm5.32da 579 . . . . . 6 (𝑥 ∈ On → ((𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦))) ↔ (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))))
124123rexbiia 3180 . . . . 5 (∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦))) ↔ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦))))))
125124abbii 2808 . . . 4 {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)))} = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))}
126125unieqi 4852 . . 3 {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = ((𝑔 ∈ V ↦ if(𝑔 = ∅, 𝑖, if(Lim dom 𝑔, ran 𝑔, (𝐹‘(𝑔 dom 𝑔)))))‘(𝑓𝑦)))} = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))}
12710, 11, 1263eqtri 2770 . 2 rec(𝐹, 𝑖) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝑖, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))}
1289, 127vtoclg 3505 1 (𝐼𝑉 → rec(𝐹, 𝐼) = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = if(𝑦 = ∅, 𝐼, if(Lim 𝑦, (𝑓𝑦), (𝐹‘(𝑓 𝑦)))))})
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 205  wa 396  w3o 1085  w3a 1086   = wceq 1539  wcel 2106  {cab 2715  wne 2943  wral 3064  wrex 3065  Vcvv 3432  cin 3886  wss 3887  c0 4256  ifcif 4459   cuni 4839  cmpt 5157  dom cdm 5589  ran crn 5590  cres 5591  cima 5592  Rel wrel 5594  Ord word 6265  Oncon0 6266  Lim wlim 6267  suc csuc 6268   Fn wfn 6428  cfv 6433  recscrecs 8201  reccrdg 8240
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1913  ax-6 1971  ax-7 2011  ax-8 2108  ax-9 2116  ax-10 2137  ax-11 2154  ax-12 2171  ax-ext 2709  ax-sep 5223  ax-nul 5230  ax-pr 5352  ax-un 7588
This theorem depends on definitions:  df-bi 206  df-an 397  df-or 845  df-3or 1087  df-3an 1088  df-tru 1542  df-fal 1552  df-ex 1783  df-nf 1787  df-sb 2068  df-mo 2540  df-eu 2569  df-clab 2716  df-cleq 2730  df-clel 2816  df-nfc 2889  df-ne 2944  df-ral 3069  df-rex 3070  df-rab 3073  df-v 3434  df-dif 3890  df-un 3892  df-in 3894  df-ss 3904  df-pss 3906  df-nul 4257  df-if 4460  df-pw 4535  df-sn 4562  df-pr 4564  df-op 4568  df-uni 4840  df-br 5075  df-opab 5137  df-mpt 5158  df-tr 5192  df-id 5489  df-eprel 5495  df-po 5503  df-so 5504  df-fr 5544  df-we 5546  df-xp 5595  df-rel 5596  df-cnv 5597  df-co 5598  df-dm 5599  df-rn 5600  df-res 5601  df-ima 5602  df-pred 6202  df-ord 6269  df-on 6270  df-lim 6271  df-suc 6272  df-iota 6391  df-fun 6435  df-fn 6436  df-f 6437  df-fo 6439  df-fv 6441  df-ov 7278  df-2nd 7832  df-frecs 8097  df-wrecs 8128  df-recs 8202  df-rdg 8241
This theorem is referenced by:  dfrdg3  33772
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