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Mathbox for Thierry Arnoux |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > relfi | Structured version Visualization version GIF version |
Description: A relation (set) is finite if and only if both its domain and range are finite. (Contributed by Thierry Arnoux, 27-Aug-2017.) |
Ref | Expression |
---|---|
relfi | ⊢ (Rel 𝐴 → (𝐴 ∈ Fin ↔ (dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dmfi 8398 | . . 3 ⊢ (𝐴 ∈ Fin → dom 𝐴 ∈ Fin) | |
2 | rnfi 8403 | . . 3 ⊢ (𝐴 ∈ Fin → ran 𝐴 ∈ Fin) | |
3 | 1, 2 | jca 501 | . 2 ⊢ (𝐴 ∈ Fin → (dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin)) |
4 | xpfi 8385 | . . . 4 ⊢ ((dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin) → (dom 𝐴 × ran 𝐴) ∈ Fin) | |
5 | relssdmrn 5798 | . . . 4 ⊢ (Rel 𝐴 → 𝐴 ⊆ (dom 𝐴 × ran 𝐴)) | |
6 | ssfi 8334 | . . . 4 ⊢ (((dom 𝐴 × ran 𝐴) ∈ Fin ∧ 𝐴 ⊆ (dom 𝐴 × ran 𝐴)) → 𝐴 ∈ Fin) | |
7 | 4, 5, 6 | syl2anr 584 | . . 3 ⊢ ((Rel 𝐴 ∧ (dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin)) → 𝐴 ∈ Fin) |
8 | 7 | ex 397 | . 2 ⊢ (Rel 𝐴 → ((dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin) → 𝐴 ∈ Fin)) |
9 | 3, 8 | impbid2 216 | 1 ⊢ (Rel 𝐴 → (𝐴 ∈ Fin ↔ (dom 𝐴 ∈ Fin ∧ ran 𝐴 ∈ Fin))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 196 ∧ wa 382 ∈ wcel 2145 ⊆ wss 3723 × cxp 5247 dom cdm 5249 ran crn 5250 Rel wrel 5254 Fincfn 8107 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1870 ax-4 1885 ax-5 1991 ax-6 2057 ax-7 2093 ax-8 2147 ax-9 2154 ax-10 2174 ax-11 2190 ax-12 2203 ax-13 2408 ax-ext 2751 ax-sep 4915 ax-nul 4923 ax-pow 4974 ax-pr 5034 ax-un 7094 |
This theorem depends on definitions: df-bi 197 df-an 383 df-or 837 df-3or 1072 df-3an 1073 df-tru 1634 df-ex 1853 df-nf 1858 df-sb 2050 df-eu 2622 df-mo 2623 df-clab 2758 df-cleq 2764 df-clel 2767 df-nfc 2902 df-ne 2944 df-ral 3066 df-rex 3067 df-reu 3068 df-rab 3070 df-v 3353 df-sbc 3588 df-csb 3683 df-dif 3726 df-un 3728 df-in 3730 df-ss 3737 df-pss 3739 df-nul 4064 df-if 4226 df-pw 4299 df-sn 4317 df-pr 4319 df-tp 4321 df-op 4323 df-uni 4575 df-int 4612 df-iun 4656 df-br 4787 df-opab 4847 df-mpt 4864 df-tr 4887 df-id 5157 df-eprel 5162 df-po 5170 df-so 5171 df-fr 5208 df-we 5210 df-xp 5255 df-rel 5256 df-cnv 5257 df-co 5258 df-dm 5259 df-rn 5260 df-res 5261 df-ima 5262 df-pred 5821 df-ord 5867 df-on 5868 df-lim 5869 df-suc 5870 df-iota 5992 df-fun 6031 df-fn 6032 df-f 6033 df-f1 6034 df-fo 6035 df-f1o 6036 df-fv 6037 df-ov 6794 df-oprab 6795 df-mpt2 6796 df-om 7211 df-1st 7313 df-2nd 7314 df-wrecs 7557 df-recs 7619 df-rdg 7657 df-1o 7711 df-oadd 7715 df-er 7894 df-en 8108 df-dom 8109 df-fin 8111 |
This theorem is referenced by: fpwrelmapffslem 29840 |
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