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Mirrors > Home > MPE Home > Th. List > ficardom | Structured version Visualization version GIF version |
Description: The cardinal number of a finite set is a finite ordinal. (Contributed by Paul Chapman, 11-Apr-2009.) (Revised by Mario Carneiro, 4-Feb-2013.) |
Ref | Expression |
---|---|
ficardom | ⊢ (𝐴 ∈ Fin → (card‘𝐴) ∈ ω) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | isfi 9014 | . . 3 ⊢ (𝐴 ∈ Fin ↔ ∃𝑥 ∈ ω 𝐴 ≈ 𝑥) | |
2 | 1 | biimpi 216 | . 2 ⊢ (𝐴 ∈ Fin → ∃𝑥 ∈ ω 𝐴 ≈ 𝑥) |
3 | finnum 9985 | . . . . . . . 8 ⊢ (𝐴 ∈ Fin → 𝐴 ∈ dom card) | |
4 | cardid2 9990 | . . . . . . . 8 ⊢ (𝐴 ∈ dom card → (card‘𝐴) ≈ 𝐴) | |
5 | 3, 4 | syl 17 | . . . . . . 7 ⊢ (𝐴 ∈ Fin → (card‘𝐴) ≈ 𝐴) |
6 | entr 9044 | . . . . . . 7 ⊢ (((card‘𝐴) ≈ 𝐴 ∧ 𝐴 ≈ 𝑥) → (card‘𝐴) ≈ 𝑥) | |
7 | 5, 6 | sylan 580 | . . . . . 6 ⊢ ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝑥) → (card‘𝐴) ≈ 𝑥) |
8 | cardon 9981 | . . . . . . 7 ⊢ (card‘𝐴) ∈ On | |
9 | onomeneq 9262 | . . . . . . 7 ⊢ (((card‘𝐴) ∈ On ∧ 𝑥 ∈ ω) → ((card‘𝐴) ≈ 𝑥 ↔ (card‘𝐴) = 𝑥)) | |
10 | 8, 9 | mpan 690 | . . . . . 6 ⊢ (𝑥 ∈ ω → ((card‘𝐴) ≈ 𝑥 ↔ (card‘𝐴) = 𝑥)) |
11 | 7, 10 | imbitrid 244 | . . . . 5 ⊢ (𝑥 ∈ ω → ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝑥) → (card‘𝐴) = 𝑥)) |
12 | eleq1a 2833 | . . . . 5 ⊢ (𝑥 ∈ ω → ((card‘𝐴) = 𝑥 → (card‘𝐴) ∈ ω)) | |
13 | 11, 12 | syld 47 | . . . 4 ⊢ (𝑥 ∈ ω → ((𝐴 ∈ Fin ∧ 𝐴 ≈ 𝑥) → (card‘𝐴) ∈ ω)) |
14 | 13 | expcomd 416 | . . 3 ⊢ (𝑥 ∈ ω → (𝐴 ≈ 𝑥 → (𝐴 ∈ Fin → (card‘𝐴) ∈ ω))) |
15 | 14 | rexlimiv 3145 | . 2 ⊢ (∃𝑥 ∈ ω 𝐴 ≈ 𝑥 → (𝐴 ∈ Fin → (card‘𝐴) ∈ ω)) |
16 | 2, 15 | mpcom 38 | 1 ⊢ (𝐴 ∈ Fin → (card‘𝐴) ∈ ω) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1536 ∈ wcel 2105 ∃wrex 3067 class class class wbr 5147 dom cdm 5688 Oncon0 6385 ‘cfv 6562 ωcom 7886 ≈ cen 8980 Fincfn 8983 cardccrd 9972 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-8 2107 ax-9 2115 ax-10 2138 ax-11 2154 ax-12 2174 ax-ext 2705 ax-sep 5301 ax-nul 5311 ax-pow 5370 ax-pr 5437 ax-un 7753 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1539 df-fal 1549 df-ex 1776 df-nf 1780 df-sb 2062 df-mo 2537 df-eu 2566 df-clab 2712 df-cleq 2726 df-clel 2813 df-nfc 2889 df-ne 2938 df-ral 3059 df-rex 3068 df-reu 3378 df-rab 3433 df-v 3479 df-sbc 3791 df-csb 3908 df-dif 3965 df-un 3967 df-in 3969 df-ss 3979 df-pss 3982 df-nul 4339 df-if 4531 df-pw 4606 df-sn 4631 df-pr 4633 df-op 4637 df-uni 4912 df-int 4951 df-br 5148 df-opab 5210 df-mpt 5231 df-tr 5265 df-id 5582 df-eprel 5588 df-po 5596 df-so 5597 df-fr 5640 df-we 5642 df-xp 5694 df-rel 5695 df-cnv 5696 df-co 5697 df-dm 5698 df-rn 5699 df-res 5700 df-ima 5701 df-ord 6388 df-on 6389 df-lim 6390 df-suc 6391 df-iota 6515 df-fun 6564 df-fn 6565 df-f 6566 df-f1 6567 df-fo 6568 df-f1o 6569 df-fv 6570 df-om 7887 df-1o 8504 df-er 8743 df-en 8984 df-dom 8985 df-sdom 8986 df-fin 8987 df-card 9976 |
This theorem is referenced by: cardnn 10000 isinffi 10029 finnisoeu 10150 iunfictbso 10151 ficardadju 10237 ficardun 10238 ficardun2 10239 pwsdompw 10240 ackbij1lem5 10260 ackbij1lem9 10264 ackbij1lem10 10265 ackbij1lem14 10269 ackbij1b 10275 ackbij2lem2 10276 ackbij2 10279 fin23lem22 10364 fin1a2lem11 10447 domtriomlem 10479 pwfseqlem4a 10698 pwfseqlem4 10699 hashkf 14367 hashginv 14369 hashcard 14390 hashcl 14391 hashdom 14414 hashun 14417 ishashinf 14498 ackbijnn 15860 mreexexd 17692 |
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