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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.) |
Ref | Expression |
---|---|
ominf | ⊢ ¬ ω ∈ Fin |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | isfi 7979 | . . 3 ⊢ (ω ∈ Fin ↔ ∃𝑥 ∈ ω ω ≈ 𝑥) | |
2 | nnord 7073 | . . . . . . . 8 ⊢ (𝑥 ∈ ω → Ord 𝑥) | |
3 | ordom 7074 | . . . . . . . 8 ⊢ Ord ω | |
4 | ordelssne 5750 | . . . . . . . 8 ⊢ ((Ord 𝑥 ∧ Ord ω) → (𝑥 ∈ ω ↔ (𝑥 ⊆ ω ∧ 𝑥 ≠ ω))) | |
5 | 2, 3, 4 | sylancl 694 | . . . . . . 7 ⊢ (𝑥 ∈ ω → (𝑥 ∈ ω ↔ (𝑥 ⊆ ω ∧ 𝑥 ≠ ω))) |
6 | 5 | ibi 256 | . . . . . 6 ⊢ (𝑥 ∈ ω → (𝑥 ⊆ ω ∧ 𝑥 ≠ ω)) |
7 | df-pss 3590 | . . . . . 6 ⊢ (𝑥 ⊊ ω ↔ (𝑥 ⊆ ω ∧ 𝑥 ≠ ω)) | |
8 | 6, 7 | sylibr 224 | . . . . 5 ⊢ (𝑥 ∈ ω → 𝑥 ⊊ ω) |
9 | ensym 8005 | . . . . 5 ⊢ (ω ≈ 𝑥 → 𝑥 ≈ ω) | |
10 | pssinf 8170 | . . . . 5 ⊢ ((𝑥 ⊊ ω ∧ 𝑥 ≈ ω) → ¬ ω ∈ Fin) | |
11 | 8, 9, 10 | syl2an 494 | . . . 4 ⊢ ((𝑥 ∈ ω ∧ ω ≈ 𝑥) → ¬ ω ∈ Fin) |
12 | 11 | rexlimiva 3028 | . . 3 ⊢ (∃𝑥 ∈ ω ω ≈ 𝑥 → ¬ ω ∈ Fin) |
13 | 1, 12 | sylbi 207 | . 2 ⊢ (ω ∈ Fin → ¬ ω ∈ Fin) |
14 | pm2.01 180 | . 2 ⊢ ((ω ∈ Fin → ¬ ω ∈ Fin) → ¬ ω ∈ Fin) | |
15 | 13, 14 | ax-mp 5 | 1 ⊢ ¬ ω ∈ Fin |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 196 ∧ wa 384 ∈ wcel 1990 ≠ wne 2794 ∃wrex 2913 ⊆ wss 3574 ⊊ wpss 3575 class class class wbr 4653 Ord word 5722 ωcom 7065 ≈ cen 7952 Fincfn 7955 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-8 1992 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 ax-sep 4781 ax-nul 4789 ax-pow 4843 ax-pr 4906 ax-un 6949 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 df-3an 1039 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-eu 2474 df-mo 2475 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-ne 2795 df-ral 2917 df-rex 2918 df-rab 2921 df-v 3202 df-sbc 3436 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-br 4654 df-opab 4713 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-om 7066 df-er 7742 df-en 7956 df-dom 7957 df-sdom 7958 df-fin 7959 |
This theorem is referenced by: fineqv 8175 nnsdomg 8219 ackbij1lem18 9059 fin23lem21 9161 fin23lem28 9162 fin23lem30 9164 isfin1-2 9207 uzinf 12764 bitsf1 15168 odhash 17989 ufinffr 21733 poimirlem30 33439 diophin 37336 diophren 37377 fiphp3d 37383 |
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