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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 5362, see enfiALT 9187. (Contributed by NM, 22-Aug-2008.) Avoid ax-pow 5362. (Revised by BTernaryTau, 23-Sep-2024.) |
Ref | Expression |
---|---|
enfi | ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin ↔ 𝐵 ∈ Fin)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ensymfib 9183 | . . . . 5 ⊢ (𝐴 ∈ Fin → (𝐴 ≈ 𝐵 ↔ 𝐵 ≈ 𝐴)) | |
2 | 1 | pm5.32i 575 | . . . 4 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝐵) ↔ (𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴)) |
3 | enfii 9185 | . . . 4 ⊢ ((𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴) → 𝐵 ∈ Fin) | |
4 | 2, 3 | sylbi 216 | . . 3 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝐵) → 𝐵 ∈ Fin) |
5 | 4 | expcom 414 | . 2 ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin → 𝐵 ∈ Fin)) |
6 | enfii 9185 | . . 3 ⊢ ((𝐵 ∈ Fin ∧ 𝐴 ≈ 𝐵) → 𝐴 ∈ Fin) | |
7 | 6 | expcom 414 | . 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 396 ∈ wcel 2106 class class class wbr 5147 ≈ cen 8932 Fincfn 8935 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2703 ax-sep 5298 ax-nul 5305 ax-pr 5426 ax-un 7721 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-3or 1088 df-3an 1089 df-tru 1544 df-fal 1554 df-ex 1782 df-nf 1786 df-sb 2068 df-mo 2534 df-eu 2563 df-clab 2710 df-cleq 2724 df-clel 2810 df-nfc 2885 df-ne 2941 df-ral 3062 df-rex 3071 df-reu 3377 df-rab 3433 df-v 3476 df-sbc 3777 df-dif 3950 df-un 3952 df-in 3954 df-ss 3964 df-pss 3966 df-nul 4322 df-if 4528 df-pw 4603 df-sn 4628 df-pr 4630 df-op 4634 df-uni 4908 df-br 5148 df-opab 5210 df-tr 5265 df-id 5573 df-eprel 5579 df-po 5587 df-so 5588 df-fr 5630 df-we 5632 df-xp 5681 df-rel 5682 df-cnv 5683 df-co 5684 df-dm 5685 df-rn 5686 df-res 5687 df-ima 5688 df-ord 6364 df-on 6365 df-lim 6366 df-suc 6367 df-iota 6492 df-fun 6542 df-fn 6543 df-f 6544 df-f1 6545 df-fo 6546 df-f1o 6547 df-fv 6548 df-om 7852 df-1o 8462 df-en 8936 df-fin 8939 |
This theorem is referenced by: enfiiOLD 9260 wofib 9536 en2eleq 9999 sdom2en01 10293 fin23lem21 10330 enfin1ai 10375 fin17 10385 isfin7-2 10387 engch 10619 uzinf 13926 hasheni 14304 isfinite4 14318 symggen 19332 psgnunilem1 19355 dfod2 19426 odhash 19436 gsumval3lem2 19768 gsumval3 19769 cyggic 21119 cusgrfilem3 28703 unidifsnel 31759 unidifsnne 31760 derangen 34151 erdsze2lem1 34182 phpreu 36460 lindsdom 36470 poimirlem30 36506 diophin 41495 diophren 41536 fiphp3d 41542 fiuneneq 41924 |
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