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Mirrors > Home > MPE Home > Th. List > isfiniteg | Structured version Visualization version GIF version |
Description: A set is finite iff it is strictly dominated by the class of natural number. Theorem 42 of [Suppes] p. 151. In order to avoid the Axiom of infinity, we include it as a hypothesis. (Contributed by NM, 3-Nov-2002.) (Revised by Mario Carneiro, 27-Apr-2015.) |
Ref | Expression |
---|---|
isfiniteg | ⊢ (ω ∈ V → (𝐴 ∈ Fin ↔ 𝐴 ≺ ω)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | isfi 8974 | . . 3 ⊢ (𝐴 ∈ Fin ↔ ∃𝑥 ∈ ω 𝐴 ≈ 𝑥) | |
2 | nnsdomg 9304 | . . . . 5 ⊢ ((ω ∈ V ∧ 𝑥 ∈ ω) → 𝑥 ≺ ω) | |
3 | sdomen1 9123 | . . . . 5 ⊢ (𝐴 ≈ 𝑥 → (𝐴 ≺ ω ↔ 𝑥 ≺ ω)) | |
4 | 2, 3 | syl5ibrcom 246 | . . . 4 ⊢ ((ω ∈ V ∧ 𝑥 ∈ ω) → (𝐴 ≈ 𝑥 → 𝐴 ≺ ω)) |
5 | 4 | rexlimdva 3149 | . . 3 ⊢ (ω ∈ V → (∃𝑥 ∈ ω 𝐴 ≈ 𝑥 → 𝐴 ≺ ω)) |
6 | 1, 5 | biimtrid 241 | . 2 ⊢ (ω ∈ V → (𝐴 ∈ Fin → 𝐴 ≺ ω)) |
7 | isfinite2 9303 | . 2 ⊢ (𝐴 ≺ ω → 𝐴 ∈ Fin) | |
8 | 6, 7 | impbid1 224 | 1 ⊢ (ω ∈ V → (𝐴 ∈ Fin ↔ 𝐴 ≺ ω)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 395 ∈ wcel 2098 ∃wrex 3064 Vcvv 3468 class class class wbr 5141 ωcom 7852 ≈ cen 8938 ≺ csdm 8940 Fincfn 8941 |
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 2697 ax-sep 5292 ax-nul 5299 ax-pow 5356 ax-pr 5420 ax-un 7722 |
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 2528 df-eu 2557 df-clab 2704 df-cleq 2718 df-clel 2804 df-nfc 2879 df-ne 2935 df-ral 3056 df-rex 3065 df-reu 3371 df-rab 3427 df-v 3470 df-sbc 3773 df-csb 3889 df-dif 3946 df-un 3948 df-in 3950 df-ss 3960 df-pss 3962 df-nul 4318 df-if 4524 df-pw 4599 df-sn 4624 df-pr 4626 df-op 4630 df-uni 4903 df-int 4944 df-iun 4992 df-br 5142 df-opab 5204 df-mpt 5225 df-tr 5259 df-id 5567 df-eprel 5573 df-po 5581 df-so 5582 df-fr 5624 df-we 5626 df-xp 5675 df-rel 5676 df-cnv 5677 df-co 5678 df-dm 5679 df-rn 5680 df-res 5681 df-ima 5682 df-pred 6294 df-ord 6361 df-on 6362 df-lim 6363 df-suc 6364 df-iota 6489 df-fun 6539 df-fn 6540 df-f 6541 df-f1 6542 df-fo 6543 df-f1o 6544 df-fv 6545 df-ov 7408 df-om 7853 df-2nd 7975 df-frecs 8267 df-wrecs 8298 df-recs 8372 df-rdg 8411 df-1o 8467 df-er 8705 df-en 8942 df-dom 8943 df-sdom 8944 df-fin 8945 |
This theorem is referenced by: unfi2 9317 unifi2 9344 isfinite 9649 axcclem 10454 |
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