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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 5325, see enfiALT 9142. (Contributed by NM, 22-Aug-2008.) Avoid ax-pow 5325. (Revised by BTernaryTau, 23-Sep-2024.) |
Ref | Expression |
---|---|
enfi | ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin ↔ 𝐵 ∈ Fin)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ensymfib 9138 | . . . . 5 ⊢ (𝐴 ∈ Fin → (𝐴 ≈ 𝐵 ↔ 𝐵 ≈ 𝐴)) | |
2 | 1 | pm5.32i 576 | . . . 4 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝐵) ↔ (𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴)) |
3 | enfii 9140 | . . . 4 ⊢ ((𝐴 ∈ Fin ∧ 𝐵 ≈ 𝐴) → 𝐵 ∈ Fin) | |
4 | 2, 3 | sylbi 216 | . . 3 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝐵) → 𝐵 ∈ Fin) |
5 | 4 | expcom 415 | . 2 ⊢ (𝐴 ≈ 𝐵 → (𝐴 ∈ Fin → 𝐵 ∈ Fin)) |
6 | enfii 9140 | . . 3 ⊢ ((𝐵 ∈ Fin ∧ 𝐴 ≈ 𝐵) → 𝐴 ∈ Fin) | |
7 | 6 | expcom 415 | . 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 397 ∈ wcel 2107 class class class wbr 5110 ≈ cen 8887 Fincfn 8890 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-10 2138 ax-11 2155 ax-12 2172 ax-ext 2708 ax-sep 5261 ax-nul 5268 ax-pr 5389 ax-un 7677 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-nf 1787 df-sb 2069 df-mo 2539 df-eu 2568 df-clab 2715 df-cleq 2729 df-clel 2815 df-nfc 2890 df-ne 2945 df-ral 3066 df-rex 3075 df-reu 3357 df-rab 3411 df-v 3450 df-sbc 3745 df-dif 3918 df-un 3920 df-in 3922 df-ss 3932 df-pss 3934 df-nul 4288 df-if 4492 df-pw 4567 df-sn 4592 df-pr 4594 df-op 4598 df-uni 4871 df-br 5111 df-opab 5173 df-tr 5228 df-id 5536 df-eprel 5542 df-po 5550 df-so 5551 df-fr 5593 df-we 5595 df-xp 5644 df-rel 5645 df-cnv 5646 df-co 5647 df-dm 5648 df-rn 5649 df-res 5650 df-ima 5651 df-ord 6325 df-on 6326 df-lim 6327 df-suc 6328 df-iota 6453 df-fun 6503 df-fn 6504 df-f 6505 df-f1 6506 df-fo 6507 df-f1o 6508 df-fv 6509 df-om 7808 df-1o 8417 df-en 8891 df-fin 8894 |
This theorem is referenced by: enfiiOLD 9215 wofib 9488 en2eleq 9951 sdom2en01 10245 fin23lem21 10282 enfin1ai 10327 fin17 10337 isfin7-2 10339 engch 10571 uzinf 13877 hasheni 14255 isfinite4 14269 symggen 19259 psgnunilem1 19282 dfod2 19353 odhash 19363 gsumval3lem2 19690 gsumval3 19691 cyggic 20995 cusgrfilem3 28447 unidifsnel 31504 unidifsnne 31505 derangen 33806 erdsze2lem1 33837 phpreu 36091 lindsdom 36101 poimirlem30 36137 diophin 41124 diophren 41165 fiphp3d 41171 fiuneneq 41553 |
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