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Theorem onnseq 7486
Description: There are no length ω decreasing sequences in the ordinals. See also noinfep 8595 for a stronger version assuming Regularity. (Contributed by Mario Carneiro, 19-May-2015.)
Assertion
Ref Expression
onnseq ((𝐹‘∅) ∈ On → ∃𝑥 ∈ ω ¬ (𝐹‘suc 𝑥) ∈ (𝐹𝑥))
Distinct variable group:   𝑥,𝐹

Proof of Theorem onnseq
Dummy variables 𝑤 𝑦 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 epweon 7025 . . . . . 6 E We On
21a1i 11 . . . . 5 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → E We On)
3 fveq2 6229 . . . . . . . . . . 11 (𝑦 = ∅ → (𝐹𝑦) = (𝐹‘∅))
43eleq1d 2715 . . . . . . . . . 10 (𝑦 = ∅ → ((𝐹𝑦) ∈ On ↔ (𝐹‘∅) ∈ On))
5 fveq2 6229 . . . . . . . . . . 11 (𝑦 = 𝑧 → (𝐹𝑦) = (𝐹𝑧))
65eleq1d 2715 . . . . . . . . . 10 (𝑦 = 𝑧 → ((𝐹𝑦) ∈ On ↔ (𝐹𝑧) ∈ On))
7 fveq2 6229 . . . . . . . . . . 11 (𝑦 = suc 𝑧 → (𝐹𝑦) = (𝐹‘suc 𝑧))
87eleq1d 2715 . . . . . . . . . 10 (𝑦 = suc 𝑧 → ((𝐹𝑦) ∈ On ↔ (𝐹‘suc 𝑧) ∈ On))
9 simpl 472 . . . . . . . . . 10 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → (𝐹‘∅) ∈ On)
10 suceq 5828 . . . . . . . . . . . . . . 15 (𝑥 = 𝑧 → suc 𝑥 = suc 𝑧)
1110fveq2d 6233 . . . . . . . . . . . . . 14 (𝑥 = 𝑧 → (𝐹‘suc 𝑥) = (𝐹‘suc 𝑧))
12 fveq2 6229 . . . . . . . . . . . . . 14 (𝑥 = 𝑧 → (𝐹𝑥) = (𝐹𝑧))
1311, 12eleq12d 2724 . . . . . . . . . . . . 13 (𝑥 = 𝑧 → ((𝐹‘suc 𝑥) ∈ (𝐹𝑥) ↔ (𝐹‘suc 𝑧) ∈ (𝐹𝑧)))
1413rspcv 3336 . . . . . . . . . . . 12 (𝑧 ∈ ω → (∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥) → (𝐹‘suc 𝑧) ∈ (𝐹𝑧)))
15 onelon 5786 . . . . . . . . . . . . 13 (((𝐹𝑧) ∈ On ∧ (𝐹‘suc 𝑧) ∈ (𝐹𝑧)) → (𝐹‘suc 𝑧) ∈ On)
1615expcom 450 . . . . . . . . . . . 12 ((𝐹‘suc 𝑧) ∈ (𝐹𝑧) → ((𝐹𝑧) ∈ On → (𝐹‘suc 𝑧) ∈ On))
1714, 16syl6 35 . . . . . . . . . . 11 (𝑧 ∈ ω → (∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥) → ((𝐹𝑧) ∈ On → (𝐹‘suc 𝑧) ∈ On)))
1817adantld 482 . . . . . . . . . 10 (𝑧 ∈ ω → (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ((𝐹𝑧) ∈ On → (𝐹‘suc 𝑧) ∈ On)))
194, 6, 8, 9, 18finds2 7136 . . . . . . . . 9 (𝑦 ∈ ω → (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → (𝐹𝑦) ∈ On))
2019com12 32 . . . . . . . 8 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → (𝑦 ∈ ω → (𝐹𝑦) ∈ On))
2120ralrimiv 2994 . . . . . . 7 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∀𝑦 ∈ ω (𝐹𝑦) ∈ On)
22 eqid 2651 . . . . . . . 8 (𝑦 ∈ ω ↦ (𝐹𝑦)) = (𝑦 ∈ ω ↦ (𝐹𝑦))
2322fmpt 6421 . . . . . . 7 (∀𝑦 ∈ ω (𝐹𝑦) ∈ On ↔ (𝑦 ∈ ω ↦ (𝐹𝑦)):ω⟶On)
2421, 23sylib 208 . . . . . 6 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → (𝑦 ∈ ω ↦ (𝐹𝑦)):ω⟶On)
25 frn 6091 . . . . . 6 ((𝑦 ∈ ω ↦ (𝐹𝑦)):ω⟶On → ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ⊆ On)
2624, 25syl 17 . . . . 5 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ⊆ On)
27 peano1 7127 . . . . . . . 8 ∅ ∈ ω
28 fdm 6089 . . . . . . . . 9 ((𝑦 ∈ ω ↦ (𝐹𝑦)):ω⟶On → dom (𝑦 ∈ ω ↦ (𝐹𝑦)) = ω)
2924, 28syl 17 . . . . . . . 8 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → dom (𝑦 ∈ ω ↦ (𝐹𝑦)) = ω)
3027, 29syl5eleqr 2737 . . . . . . 7 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∅ ∈ dom (𝑦 ∈ ω ↦ (𝐹𝑦)))
31 ne0i 3954 . . . . . . 7 (∅ ∈ dom (𝑦 ∈ ω ↦ (𝐹𝑦)) → dom (𝑦 ∈ ω ↦ (𝐹𝑦)) ≠ ∅)
3230, 31syl 17 . . . . . 6 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → dom (𝑦 ∈ ω ↦ (𝐹𝑦)) ≠ ∅)
33 dm0rn0 5374 . . . . . . 7 (dom (𝑦 ∈ ω ↦ (𝐹𝑦)) = ∅ ↔ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) = ∅)
3433necon3bii 2875 . . . . . 6 (dom (𝑦 ∈ ω ↦ (𝐹𝑦)) ≠ ∅ ↔ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ≠ ∅)
3532, 34sylib 208 . . . . 5 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ≠ ∅)
36 wefrc 5137 . . . . 5 (( E We On ∧ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ⊆ On ∧ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ≠ ∅) → ∃𝑧 ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦))(ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅)
372, 26, 35, 36syl3anc 1366 . . . 4 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∃𝑧 ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦))(ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅)
38 fvex 6239 . . . . . 6 (𝐹𝑤) ∈ V
3938rgenw 2953 . . . . 5 𝑤 ∈ ω (𝐹𝑤) ∈ V
40 fveq2 6229 . . . . . . 7 (𝑦 = 𝑤 → (𝐹𝑦) = (𝐹𝑤))
4140cbvmptv 4783 . . . . . 6 (𝑦 ∈ ω ↦ (𝐹𝑦)) = (𝑤 ∈ ω ↦ (𝐹𝑤))
42 ineq2 3841 . . . . . . 7 (𝑧 = (𝐹𝑤) → (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)))
4342eqeq1d 2653 . . . . . 6 (𝑧 = (𝐹𝑤) → ((ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅ ↔ (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅))
4441, 43rexrnmpt 6409 . . . . 5 (∀𝑤 ∈ ω (𝐹𝑤) ∈ V → (∃𝑧 ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦))(ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅ ↔ ∃𝑤 ∈ ω (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅))
4539, 44ax-mp 5 . . . 4 (∃𝑧 ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦))(ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅ ↔ ∃𝑤 ∈ ω (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅)
4637, 45sylib 208 . . 3 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∃𝑤 ∈ ω (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅)
47 peano2 7128 . . . . . . . . 9 (𝑤 ∈ ω → suc 𝑤 ∈ ω)
4847adantl 481 . . . . . . . 8 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → suc 𝑤 ∈ ω)
49 eqid 2651 . . . . . . . 8 (𝐹‘suc 𝑤) = (𝐹‘suc 𝑤)
50 fveq2 6229 . . . . . . . . . 10 (𝑦 = suc 𝑤 → (𝐹𝑦) = (𝐹‘suc 𝑤))
5150eqeq2d 2661 . . . . . . . . 9 (𝑦 = suc 𝑤 → ((𝐹‘suc 𝑤) = (𝐹𝑦) ↔ (𝐹‘suc 𝑤) = (𝐹‘suc 𝑤)))
5251rspcev 3340 . . . . . . . 8 ((suc 𝑤 ∈ ω ∧ (𝐹‘suc 𝑤) = (𝐹‘suc 𝑤)) → ∃𝑦 ∈ ω (𝐹‘suc 𝑤) = (𝐹𝑦))
5348, 49, 52sylancl 695 . . . . . . 7 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → ∃𝑦 ∈ ω (𝐹‘suc 𝑤) = (𝐹𝑦))
54 fvex 6239 . . . . . . . 8 (𝐹‘suc 𝑤) ∈ V
5522elrnmpt 5404 . . . . . . . 8 ((𝐹‘suc 𝑤) ∈ V → ((𝐹‘suc 𝑤) ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ↔ ∃𝑦 ∈ ω (𝐹‘suc 𝑤) = (𝐹𝑦)))
5654, 55ax-mp 5 . . . . . . 7 ((𝐹‘suc 𝑤) ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ↔ ∃𝑦 ∈ ω (𝐹‘suc 𝑤) = (𝐹𝑦))
5753, 56sylibr 224 . . . . . 6 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → (𝐹‘suc 𝑤) ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦)))
58 suceq 5828 . . . . . . . . . 10 (𝑥 = 𝑤 → suc 𝑥 = suc 𝑤)
5958fveq2d 6233 . . . . . . . . 9 (𝑥 = 𝑤 → (𝐹‘suc 𝑥) = (𝐹‘suc 𝑤))
60 fveq2 6229 . . . . . . . . 9 (𝑥 = 𝑤 → (𝐹𝑥) = (𝐹𝑤))
6159, 60eleq12d 2724 . . . . . . . 8 (𝑥 = 𝑤 → ((𝐹‘suc 𝑥) ∈ (𝐹𝑥) ↔ (𝐹‘suc 𝑤) ∈ (𝐹𝑤)))
6261rspccva 3339 . . . . . . 7 ((∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥) ∧ 𝑤 ∈ ω) → (𝐹‘suc 𝑤) ∈ (𝐹𝑤))
6362adantll 750 . . . . . 6 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → (𝐹‘suc 𝑤) ∈ (𝐹𝑤))
64 inelcm 4065 . . . . . 6 (((𝐹‘suc 𝑤) ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∧ (𝐹‘suc 𝑤) ∈ (𝐹𝑤)) → (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) ≠ ∅)
6557, 63, 64syl2anc 694 . . . . 5 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) ≠ ∅)
6665neneqd 2828 . . . 4 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → ¬ (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅)
6766nrexdv 3030 . . 3 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ¬ ∃𝑤 ∈ ω (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅)
6846, 67pm2.65da 599 . 2 ((𝐹‘∅) ∈ On → ¬ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥))
69 rexnal 3024 . 2 (∃𝑥 ∈ ω ¬ (𝐹‘suc 𝑥) ∈ (𝐹𝑥) ↔ ¬ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥))
7068, 69sylibr 224 1 ((𝐹‘∅) ∈ On → ∃𝑥 ∈ ω ¬ (𝐹‘suc 𝑥) ∈ (𝐹𝑥))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 196  wa 383   = wceq 1523  wcel 2030  wne 2823  wral 2941  wrex 2942  Vcvv 3231  cin 3606  wss 3607  c0 3948  cmpt 4762   E cep 5057   We wwe 5101  dom cdm 5143  ran crn 5144  Oncon0 5761  suc csuc 5763  wf 5922  cfv 5926  ωcom 7107
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1762  ax-4 1777  ax-5 1879  ax-6 1945  ax-7 1981  ax-8 2032  ax-9 2039  ax-10 2059  ax-11 2074  ax-12 2087  ax-13 2282  ax-ext 2631  ax-sep 4814  ax-nul 4822  ax-pow 4873  ax-pr 4936  ax-un 6991
This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-3or 1055  df-3an 1056  df-tru 1526  df-ex 1745  df-nf 1750  df-sb 1938  df-eu 2502  df-mo 2503  df-clab 2638  df-cleq 2644  df-clel 2647  df-nfc 2782  df-ne 2824  df-ral 2946  df-rex 2947  df-rab 2950  df-v 3233  df-sbc 3469  df-csb 3567  df-dif 3610  df-un 3612  df-in 3614  df-ss 3621  df-pss 3623  df-nul 3949  df-if 4120  df-pw 4193  df-sn 4211  df-pr 4213  df-tp 4215  df-op 4217  df-uni 4469  df-br 4686  df-opab 4746  df-mpt 4763  df-tr 4786  df-id 5053  df-eprel 5058  df-po 5064  df-so 5065  df-fr 5102  df-we 5104  df-xp 5149  df-rel 5150  df-cnv 5151  df-co 5152  df-dm 5153  df-rn 5154  df-res 5155  df-ima 5156  df-ord 5764  df-on 5765  df-lim 5766  df-suc 5767  df-iota 5889  df-fun 5928  df-fn 5929  df-f 5930  df-fv 5934  df-om 7108
This theorem is referenced by: (None)
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