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Mirrors > Home > MPE Home > Th. List > enfi | Structured version Visualization version GIF version |
Description: Equinumerous sets have the same finiteness. For a shorter proof using ax-pow 5354, see enfiALT 9188. (Contributed by NM, 22-Aug-2008.) Avoid ax-pow 5354. (Revised by BTernaryTau, 23-Sep-2024.) |
Ref | Expression |
---|---|
enfi | ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin ↔ 𝐵 ∈ Fin)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ensymfib 9184 | . . . . 5 ⊢ (𝐴 ∈ Fin → (𝐴 ≈ 𝐵 ↔ 𝐵 ≈ 𝐴)) | |
2 | 1 | pm5.32i 574 | . . . 4 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝐵) ↔ (𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴)) |
3 | enfii 9186 | . . . 4 ⊢ ((𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴) → 𝐵 ∈ Fin) | |
4 | 2, 3 | sylbi 216 | . . 3 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝐵) → 𝐵 ∈ Fin) |
5 | 4 | expcom 413 | . 2 ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin → 𝐵 ∈ Fin)) |
6 | enfii 9186 | . . 3 ⊢ ((𝐵 ∈ Fin ∧ 𝐴 ≈ 𝐵) → 𝐴 ∈ Fin) | |
7 | 6 | expcom 413 | . 2 ⊢ (𝐴 ≈ 𝐵 → (𝐵 ∈ Fin → 𝐴 ∈ Fin)) |
8 | 5, 7 | impbid 211 | 1 ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin ↔ 𝐵 ∈ Fin)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 395 ∈ wcel 2098 class class class wbr 5139 ≈ cen 8933 Fincfn 8936 |
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 2695 ax-sep 5290 ax-nul 5297 ax-pr 5418 ax-un 7719 |
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 2526 df-eu 2555 df-clab 2702 df-cleq 2716 df-clel 2802 df-nfc 2877 df-ne 2933 df-ral 3054 df-rex 3063 df-reu 3369 df-rab 3425 df-v 3468 df-sbc 3771 df-dif 3944 df-un 3946 df-in 3948 df-ss 3958 df-pss 3960 df-nul 4316 df-if 4522 df-pw 4597 df-sn 4622 df-pr 4624 df-op 4628 df-uni 4901 df-br 5140 df-opab 5202 df-tr 5257 df-id 5565 df-eprel 5571 df-po 5579 df-so 5580 df-fr 5622 df-we 5624 df-xp 5673 df-rel 5674 df-cnv 5675 df-co 5676 df-dm 5677 df-rn 5678 df-res 5679 df-ima 5680 df-ord 6358 df-on 6359 df-lim 6360 df-suc 6361 df-iota 6486 df-fun 6536 df-fn 6537 df-f 6538 df-f1 6539 df-fo 6540 df-f1o 6541 df-fv 6542 df-om 7850 df-1o 8462 df-en 8937 df-fin 8940 |
This theorem is referenced by: enfiiOLD 9261 wofib 9537 en2eleq 10000 sdom2en01 10294 fin23lem21 10331 enfin1ai 10376 fin17 10386 isfin7-2 10388 engch 10620 uzinf 13928 hasheni 14306 isfinite4 14320 symggen 19382 psgnunilem1 19405 dfod2 19476 odhash 19486 gsumval3lem2 19818 gsumval3 19819 cyggic 21437 cusgrfilem3 29186 unidifsnel 32244 unidifsnne 32245 derangen 34654 erdsze2lem1 34685 phpreu 36966 lindsdom 36976 poimirlem30 37012 diophin 42024 diophren 42065 fiphp3d 42071 fiuneneq 42453 |
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