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Theorem onnseq 7426
Description: There are no length ω decreasing sequences in the ordinals. See also noinfep 8542 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 6968 . . . . . 6 E We On
21a1i 11 . . . . 5 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → E We On)
3 fveq2 6178 . . . . . . . . . . 11 (𝑦 = ∅ → (𝐹𝑦) = (𝐹‘∅))
43eleq1d 2684 . . . . . . . . . 10 (𝑦 = ∅ → ((𝐹𝑦) ∈ On ↔ (𝐹‘∅) ∈ On))
5 fveq2 6178 . . . . . . . . . . 11 (𝑦 = 𝑧 → (𝐹𝑦) = (𝐹𝑧))
65eleq1d 2684 . . . . . . . . . 10 (𝑦 = 𝑧 → ((𝐹𝑦) ∈ On ↔ (𝐹𝑧) ∈ On))
7 fveq2 6178 . . . . . . . . . . 11 (𝑦 = suc 𝑧 → (𝐹𝑦) = (𝐹‘suc 𝑧))
87eleq1d 2684 . . . . . . . . . 10 (𝑦 = suc 𝑧 → ((𝐹𝑦) ∈ On ↔ (𝐹‘suc 𝑧) ∈ On))
9 simpl 473 . . . . . . . . . 10 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → (𝐹‘∅) ∈ On)
10 suceq 5778 . . . . . . . . . . . . . . 15 (𝑥 = 𝑧 → suc 𝑥 = suc 𝑧)
1110fveq2d 6182 . . . . . . . . . . . . . 14 (𝑥 = 𝑧 → (𝐹‘suc 𝑥) = (𝐹‘suc 𝑧))
12 fveq2 6178 . . . . . . . . . . . . . 14 (𝑥 = 𝑧 → (𝐹𝑥) = (𝐹𝑧))
1311, 12eleq12d 2693 . . . . . . . . . . . . 13 (𝑥 = 𝑧 → ((𝐹‘suc 𝑥) ∈ (𝐹𝑥) ↔ (𝐹‘suc 𝑧) ∈ (𝐹𝑧)))
1413rspcv 3300 . . . . . . . . . . . 12 (𝑧 ∈ ω → (∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥) → (𝐹‘suc 𝑧) ∈ (𝐹𝑧)))
15 onelon 5736 . . . . . . . . . . . . 13 (((𝐹𝑧) ∈ On ∧ (𝐹‘suc 𝑧) ∈ (𝐹𝑧)) → (𝐹‘suc 𝑧) ∈ On)
1615expcom 451 . . . . . . . . . . . 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 483 . . . . . . . . . 10 (𝑧 ∈ ω → (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ((𝐹𝑧) ∈ On → (𝐹‘suc 𝑧) ∈ On)))
194, 6, 8, 9, 18finds2 7079 . . . . . . . . 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 2962 . . . . . . 7 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∀𝑦 ∈ ω (𝐹𝑦) ∈ On)
22 eqid 2620 . . . . . . . 8 (𝑦 ∈ ω ↦ (𝐹𝑦)) = (𝑦 ∈ ω ↦ (𝐹𝑦))
2322fmpt 6367 . . . . . . 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 6040 . . . . . 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 7070 . . . . . . . 8 ∅ ∈ ω
28 fdm 6038 . . . . . . . . 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 2706 . . . . . . 7 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∅ ∈ dom (𝑦 ∈ ω ↦ (𝐹𝑦)))
31 ne0i 3913 . . . . . . 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 5331 . . . . . . 7 (dom (𝑦 ∈ ω ↦ (𝐹𝑦)) = ∅ ↔ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) = ∅)
3433necon3bii 2843 . . . . . 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 5098 . . . . 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 1324 . . . 4 (((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) → ∃𝑧 ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦))(ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅)
38 fvex 6188 . . . . . 6 (𝐹𝑤) ∈ V
3938rgenw 2921 . . . . 5 𝑤 ∈ ω (𝐹𝑤) ∈ V
40 fveq2 6178 . . . . . . 7 (𝑦 = 𝑤 → (𝐹𝑦) = (𝐹𝑤))
4140cbvmptv 4741 . . . . . 6 (𝑦 ∈ ω ↦ (𝐹𝑦)) = (𝑤 ∈ ω ↦ (𝐹𝑤))
42 ineq2 3800 . . . . . . 7 (𝑧 = (𝐹𝑤) → (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)))
4342eqeq1d 2622 . . . . . 6 (𝑧 = (𝐹𝑤) → ((ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ 𝑧) = ∅ ↔ (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅))
4441, 43rexrnmpt 6355 . . . . 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 7071 . . . . . . . . 9 (𝑤 ∈ ω → suc 𝑤 ∈ ω)
4847adantl 482 . . . . . . . 8 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → suc 𝑤 ∈ ω)
49 eqid 2620 . . . . . . . 8 (𝐹‘suc 𝑤) = (𝐹‘suc 𝑤)
50 fveq2 6178 . . . . . . . . . 10 (𝑦 = suc 𝑤 → (𝐹𝑦) = (𝐹‘suc 𝑤))
5150eqeq2d 2630 . . . . . . . . 9 (𝑦 = suc 𝑤 → ((𝐹‘suc 𝑤) = (𝐹𝑦) ↔ (𝐹‘suc 𝑤) = (𝐹‘suc 𝑤)))
5251rspcev 3304 . . . . . . . 8 ((suc 𝑤 ∈ ω ∧ (𝐹‘suc 𝑤) = (𝐹‘suc 𝑤)) → ∃𝑦 ∈ ω (𝐹‘suc 𝑤) = (𝐹𝑦))
5348, 49, 52sylancl 693 . . . . . . 7 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → ∃𝑦 ∈ ω (𝐹‘suc 𝑤) = (𝐹𝑦))
54 fvex 6188 . . . . . . . 8 (𝐹‘suc 𝑤) ∈ V
5522elrnmpt 5361 . . . . . . . 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 5778 . . . . . . . . . 10 (𝑥 = 𝑤 → suc 𝑥 = suc 𝑤)
5958fveq2d 6182 . . . . . . . . 9 (𝑥 = 𝑤 → (𝐹‘suc 𝑥) = (𝐹‘suc 𝑤))
60 fveq2 6178 . . . . . . . . 9 (𝑥 = 𝑤 → (𝐹𝑥) = (𝐹𝑤))
6159, 60eleq12d 2693 . . . . . . . 8 (𝑥 = 𝑤 → ((𝐹‘suc 𝑥) ∈ (𝐹𝑥) ↔ (𝐹‘suc 𝑤) ∈ (𝐹𝑤)))
6261rspccva 3303 . . . . . . 7 ((∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥) ∧ 𝑤 ∈ ω) → (𝐹‘suc 𝑤) ∈ (𝐹𝑤))
6362adantll 749 . . . . . 6 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → (𝐹‘suc 𝑤) ∈ (𝐹𝑤))
64 inelcm 4023 . . . . . 6 (((𝐹‘suc 𝑤) ∈ ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∧ (𝐹‘suc 𝑤) ∈ (𝐹𝑤)) → (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) ≠ ∅)
6557, 63, 64syl2anc 692 . . . . 5 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) ≠ ∅)
6665neneqd 2796 . . . 4 ((((𝐹‘∅) ∈ On ∧ ∀𝑥 ∈ ω (𝐹‘suc 𝑥) ∈ (𝐹𝑥)) ∧ 𝑤 ∈ ω) → ¬ (ran (𝑦 ∈ ω ↦ (𝐹𝑦)) ∩ (𝐹𝑤)) = ∅)
6766nrexdv 2998 . . 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 2992 . 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 384   = wceq 1481  wcel 1988  wne 2791  wral 2909  wrex 2910  Vcvv 3195  cin 3566  wss 3567  c0 3907  cmpt 4720   E cep 5018   We wwe 5062  dom cdm 5104  ran crn 5105  Oncon0 5711  suc csuc 5713  wf 5872  cfv 5876  ωcom 7050
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1720  ax-4 1735  ax-5 1837  ax-6 1886  ax-7 1933  ax-8 1990  ax-9 1997  ax-10 2017  ax-11 2032  ax-12 2045  ax-13 2244  ax-ext 2600  ax-sep 4772  ax-nul 4780  ax-pow 4834  ax-pr 4897  ax-un 6934
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1037  df-3an 1038  df-tru 1484  df-ex 1703  df-nf 1708  df-sb 1879  df-eu 2472  df-mo 2473  df-clab 2607  df-cleq 2613  df-clel 2616  df-nfc 2751  df-ne 2792  df-ral 2914  df-rex 2915  df-rab 2918  df-v 3197  df-sbc 3430  df-csb 3527  df-dif 3570  df-un 3572  df-in 3574  df-ss 3581  df-pss 3583  df-nul 3908  df-if 4078  df-pw 4151  df-sn 4169  df-pr 4171  df-tp 4173  df-op 4175  df-uni 4428  df-br 4645  df-opab 4704  df-mpt 4721  df-tr 4744  df-id 5014  df-eprel 5019  df-po 5025  df-so 5026  df-fr 5063  df-we 5065  df-xp 5110  df-rel 5111  df-cnv 5112  df-co 5113  df-dm 5114  df-rn 5115  df-res 5116  df-ima 5117  df-ord 5714  df-on 5715  df-lim 5716  df-suc 5717  df-iota 5839  df-fun 5878  df-fn 5879  df-f 5880  df-fv 5884  df-om 7051
This theorem is referenced by: (None)
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