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Mirrors > Home > MPE Home > Th. List > ominf | Structured version Visualization version GIF version |
Description: The set of natural numbers is infinite. Corollary 6D(b) of [Enderton] p. 136. (Contributed by NM, 2-Jun-1998.) Avoid ax-pow 5365. (Revised by BTernaryTau, 2-Jan-2025.) |
Ref | Expression |
---|---|
ominf | ⊢ ¬ ω ∈ Fin |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | isfi 8997 | . . 3 ⊢ (ω ∈ Fin ↔ ∃𝑥 ∈ ω ω ≈ 𝑥) | |
2 | nnord 7878 | . . . . . . . 8 ⊢ (𝑥 ∈ ω → Ord 𝑥) | |
3 | ordom 7880 | . . . . . . . 8 ⊢ Ord ω | |
4 | ordelssne 6396 | . . . . . . . 8 ⊢ ((Ord 𝑥 ∧ Ord ω) → (𝑥 ∈ ω ↔ (𝑥 ⊆ ω ∧ 𝑥 ≠ ω))) | |
5 | 2, 3, 4 | sylancl 585 | . . . . . . 7 ⊢ (𝑥 ∈ ω → (𝑥 ∈ ω ↔ (𝑥 ⊆ ω ∧ 𝑥 ≠ ω))) |
6 | 5 | ibi 267 | . . . . . 6 ⊢ (𝑥 ∈ ω → (𝑥 ⊆ ω ∧ 𝑥 ≠ ω)) |
7 | df-pss 3966 | . . . . . 6 ⊢ (𝑥 ⊊ ω ↔ (𝑥 ⊆ ω ∧ 𝑥 ≠ ω)) | |
8 | 6, 7 | sylibr 233 | . . . . 5 ⊢ (𝑥 ∈ ω → 𝑥 ⊊ ω) |
9 | nnfi 9192 | . . . . . . 7 ⊢ (𝑥 ∈ ω → 𝑥 ∈ Fin) | |
10 | ensymfib 9212 | . . . . . . 7 ⊢ (𝑥 ∈ Fin → (𝑥 ≈ ω ↔ ω ≈ 𝑥)) | |
11 | 9, 10 | syl 17 | . . . . . 6 ⊢ (𝑥 ∈ ω → (𝑥 ≈ ω ↔ ω ≈ 𝑥)) |
12 | 11 | biimpar 477 | . . . . 5 ⊢ ((𝑥 ∈ ω ∧ ω ≈ 𝑥) → 𝑥 ≈ ω) |
13 | pssinf 9281 | . . . . 5 ⊢ ((𝑥 ⊊ ω ∧ 𝑥 ≈ ω) → ¬ ω ∈ Fin) | |
14 | 8, 12, 13 | syl2an2r 684 | . . . 4 ⊢ ((𝑥 ∈ ω ∧ ω ≈ 𝑥) → ¬ ω ∈ Fin) |
15 | 14 | rexlimiva 3144 | . . 3 ⊢ (∃𝑥 ∈ ω ω ≈ 𝑥 → ¬ ω ∈ Fin) |
16 | 1, 15 | sylbi 216 | . 2 ⊢ (ω ∈ Fin → ¬ ω ∈ Fin) |
17 | pm2.01 188 | . 2 ⊢ ((ω ∈ Fin → ¬ ω ∈ Fin) → ¬ ω ∈ Fin) | |
18 | 16, 17 | ax-mp 5 | 1 ⊢ ¬ ω ∈ Fin |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∧ wa 395 ∈ wcel 2099 ≠ wne 2937 ∃wrex 3067 ⊆ wss 3947 ⊊ wpss 3948 class class class wbr 5148 Ord word 6368 ωcom 7870 ≈ cen 8961 Fincfn 8964 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2167 ax-ext 2699 ax-sep 5299 ax-nul 5306 ax-pr 5429 ax-un 7740 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 847 df-3or 1086 df-3an 1087 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2530 df-eu 2559 df-clab 2706 df-cleq 2720 df-clel 2806 df-nfc 2881 df-ne 2938 df-ral 3059 df-rex 3068 df-reu 3374 df-rab 3430 df-v 3473 df-sbc 3777 df-csb 3893 df-dif 3950 df-un 3952 df-in 3954 df-ss 3964 df-pss 3966 df-nul 4324 df-if 4530 df-pw 4605 df-sn 4630 df-pr 4632 df-op 4636 df-uni 4909 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5576 df-eprel 5582 df-po 5590 df-so 5591 df-fr 5633 df-we 5635 df-xp 5684 df-rel 5685 df-cnv 5686 df-co 5687 df-dm 5688 df-rn 5689 df-res 5690 df-ima 5691 df-ord 6372 df-on 6373 df-lim 6374 df-suc 6375 df-iota 6500 df-fun 6550 df-fn 6551 df-f 6552 df-f1 6553 df-fo 6554 df-f1o 6555 df-fv 6556 df-om 7871 df-1o 8487 df-en 8965 df-dom 8966 df-sdom 8967 df-fin 8968 |
This theorem is referenced by: fineqv 9288 nnsdomg 9327 nnsdomgOLD 9328 ackbij1lem18 10261 fin23lem21 10363 fin23lem28 10364 fin23lem30 10366 isfin1-2 10409 uzinf 13963 bitsf1 16421 odhash 19529 ufinffr 23846 poimirlem30 37123 diophin 42192 diophren 42233 fiphp3d 42239 |
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