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Theorem tfrlem16 8394
Description: Lemma for finite recursion. Without assuming ax-rep 5278, we can show that the domain of the constructed function is a limit ordinal, and hence contains all the finite ordinals. (Contributed by Mario Carneiro, 14-Nov-2014.)
Hypothesis
Ref Expression
tfrlem.1 𝐴 = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))}
Assertion
Ref Expression
tfrlem16 Lim dom recs(𝐹)
Distinct variable group:   𝑥,𝑓,𝑦,𝐹
Allowed substitution hints:   𝐴(𝑥,𝑦,𝑓)

Proof of Theorem tfrlem16
Dummy variable 𝑧 is distinct from all other variables.
StepHypRef Expression
1 tfrlem.1 . . . 4 𝐴 = {𝑓 ∣ ∃𝑥 ∈ On (𝑓 Fn 𝑥 ∧ ∀𝑦𝑥 (𝑓𝑦) = (𝐹‘(𝑓𝑦)))}
21tfrlem8 8385 . . 3 Ord dom recs(𝐹)
3 ordzsl 7831 . . 3 (Ord dom recs(𝐹) ↔ (dom recs(𝐹) = ∅ ∨ ∃𝑧 ∈ On dom recs(𝐹) = suc 𝑧 ∨ Lim dom recs(𝐹)))
42, 3mpbi 229 . 2 (dom recs(𝐹) = ∅ ∨ ∃𝑧 ∈ On dom recs(𝐹) = suc 𝑧 ∨ Lim dom recs(𝐹))
5 res0 5979 . . . . . . 7 (recs(𝐹) ↾ ∅) = ∅
6 0ex 5300 . . . . . . 7 ∅ ∈ V
75, 6eqeltri 2823 . . . . . 6 (recs(𝐹) ↾ ∅) ∈ V
8 0elon 6412 . . . . . . 7 ∅ ∈ On
91tfrlem15 8393 . . . . . . 7 (∅ ∈ On → (∅ ∈ dom recs(𝐹) ↔ (recs(𝐹) ↾ ∅) ∈ V))
108, 9ax-mp 5 . . . . . 6 (∅ ∈ dom recs(𝐹) ↔ (recs(𝐹) ↾ ∅) ∈ V)
117, 10mpbir 230 . . . . 5 ∅ ∈ dom recs(𝐹)
1211n0ii 4331 . . . 4 ¬ dom recs(𝐹) = ∅
1312pm2.21i 119 . . 3 (dom recs(𝐹) = ∅ → Lim dom recs(𝐹))
141tfrlem13 8391 . . . . 5 ¬ recs(𝐹) ∈ V
15 simpr 484 . . . . . . . . . 10 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → dom recs(𝐹) = suc 𝑧)
16 df-suc 6364 . . . . . . . . . 10 suc 𝑧 = (𝑧 ∪ {𝑧})
1715, 16eqtrdi 2782 . . . . . . . . 9 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → dom recs(𝐹) = (𝑧 ∪ {𝑧}))
1817reseq2d 5975 . . . . . . . 8 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → (recs(𝐹) ↾ dom recs(𝐹)) = (recs(𝐹) ↾ (𝑧 ∪ {𝑧})))
191tfrlem6 8383 . . . . . . . . 9 Rel recs(𝐹)
20 resdm 6020 . . . . . . . . 9 (Rel recs(𝐹) → (recs(𝐹) ↾ dom recs(𝐹)) = recs(𝐹))
2119, 20ax-mp 5 . . . . . . . 8 (recs(𝐹) ↾ dom recs(𝐹)) = recs(𝐹)
22 resundi 5989 . . . . . . . 8 (recs(𝐹) ↾ (𝑧 ∪ {𝑧})) = ((recs(𝐹) ↾ 𝑧) ∪ (recs(𝐹) ↾ {𝑧}))
2318, 21, 223eqtr3g 2789 . . . . . . 7 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → recs(𝐹) = ((recs(𝐹) ↾ 𝑧) ∪ (recs(𝐹) ↾ {𝑧})))
24 vex 3472 . . . . . . . . . . 11 𝑧 ∈ V
2524sucid 6440 . . . . . . . . . 10 𝑧 ∈ suc 𝑧
2625, 15eleqtrrid 2834 . . . . . . . . 9 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → 𝑧 ∈ dom recs(𝐹))
271tfrlem9a 8387 . . . . . . . . 9 (𝑧 ∈ dom recs(𝐹) → (recs(𝐹) ↾ 𝑧) ∈ V)
2826, 27syl 17 . . . . . . . 8 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → (recs(𝐹) ↾ 𝑧) ∈ V)
29 snex 5424 . . . . . . . . 9 {⟨𝑧, (recs(𝐹)‘𝑧)⟩} ∈ V
301tfrlem7 8384 . . . . . . . . . 10 Fun recs(𝐹)
31 funressn 7153 . . . . . . . . . 10 (Fun recs(𝐹) → (recs(𝐹) ↾ {𝑧}) ⊆ {⟨𝑧, (recs(𝐹)‘𝑧)⟩})
3230, 31ax-mp 5 . . . . . . . . 9 (recs(𝐹) ↾ {𝑧}) ⊆ {⟨𝑧, (recs(𝐹)‘𝑧)⟩}
3329, 32ssexi 5315 . . . . . . . 8 (recs(𝐹) ↾ {𝑧}) ∈ V
34 unexg 7733 . . . . . . . 8 (((recs(𝐹) ↾ 𝑧) ∈ V ∧ (recs(𝐹) ↾ {𝑧}) ∈ V) → ((recs(𝐹) ↾ 𝑧) ∪ (recs(𝐹) ↾ {𝑧})) ∈ V)
3528, 33, 34sylancl 585 . . . . . . 7 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → ((recs(𝐹) ↾ 𝑧) ∪ (recs(𝐹) ↾ {𝑧})) ∈ V)
3623, 35eqeltrd 2827 . . . . . 6 ((𝑧 ∈ On ∧ dom recs(𝐹) = suc 𝑧) → recs(𝐹) ∈ V)
3736rexlimiva 3141 . . . . 5 (∃𝑧 ∈ On dom recs(𝐹) = suc 𝑧 → recs(𝐹) ∈ V)
3814, 37mto 196 . . . 4 ¬ ∃𝑧 ∈ On dom recs(𝐹) = suc 𝑧
3938pm2.21i 119 . . 3 (∃𝑧 ∈ On dom recs(𝐹) = suc 𝑧 → Lim dom recs(𝐹))
40 id 22 . . 3 (Lim dom recs(𝐹) → Lim dom recs(𝐹))
4113, 39, 403jaoi 1424 . 2 ((dom recs(𝐹) = ∅ ∨ ∃𝑧 ∈ On dom recs(𝐹) = suc 𝑧 ∨ Lim dom recs(𝐹)) → Lim dom recs(𝐹))
424, 41ax-mp 5 1 Lim dom recs(𝐹)
Colors of variables: wff setvar class
Syntax hints:  wb 205  wa 395  w3o 1083   = wceq 1533  wcel 2098  {cab 2703  wral 3055  wrex 3064  Vcvv 3468  cun 3941  wss 3943  c0 4317  {csn 4623  cop 4629  dom cdm 5669  cres 5671  Rel wrel 5674  Ord word 6357  Oncon0 6358  Lim wlim 6359  suc csuc 6360  Fun wfun 6531   Fn wfn 6532  cfv 6537  recscrecs 8371
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-10 2129  ax-11 2146  ax-12 2163  ax-ext 2697  ax-sep 5292  ax-nul 5299  ax-pr 5420  ax-un 7722
This theorem depends on definitions:  df-bi 206  df-an 396  df-or 845  df-3or 1085  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-nf 1778  df-sb 2060  df-mo 2528  df-eu 2557  df-clab 2704  df-cleq 2718  df-clel 2804  df-nfc 2879  df-ne 2935  df-ral 3056  df-rex 3065  df-reu 3371  df-rab 3427  df-v 3470  df-sbc 3773  df-csb 3889  df-dif 3946  df-un 3948  df-in 3950  df-ss 3960  df-pss 3962  df-nul 4318  df-if 4524  df-pw 4599  df-sn 4624  df-pr 4626  df-op 4630  df-uni 4903  df-iun 4992  df-br 5142  df-opab 5204  df-mpt 5225  df-tr 5259  df-id 5567  df-eprel 5573  df-po 5581  df-so 5582  df-fr 5624  df-we 5626  df-xp 5675  df-rel 5676  df-cnv 5677  df-co 5678  df-dm 5679  df-rn 5680  df-res 5681  df-ima 5682  df-pred 6294  df-ord 6361  df-on 6362  df-lim 6363  df-suc 6364  df-iota 6489  df-fun 6539  df-fn 6540  df-f 6541  df-f1 6542  df-fo 6543  df-f1o 6544  df-fv 6545  df-ov 7408  df-2nd 7975  df-frecs 8267  df-wrecs 8298  df-recs 8372
This theorem is referenced by:  tfr1a  8395
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