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Mirrors > Home > MPE Home > Th. List > ptfinfin | Structured version Visualization version GIF version |
Description: A point covered by a point-finite cover is only covered by finitely many elements. (Contributed by Jeff Hankins, 21-Jan-2010.) |
Ref | Expression |
---|---|
ptfinfin.1 | ⊢ 𝑋 = ∪ 𝐴 |
Ref | Expression |
---|---|
ptfinfin | ⊢ ((𝐴 ∈ PtFin ∧ 𝑃 ∈ 𝑋) → {𝑥 ∈ 𝐴 ∣ 𝑃 ∈ 𝑥} ∈ Fin) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ptfinfin.1 | . . . . 5 ⊢ 𝑋 = ∪ 𝐴 | |
2 | 1 | isptfin 23464 | . . . 4 ⊢ (𝐴 ∈ PtFin → (𝐴 ∈ PtFin ↔ ∀𝑝 ∈ 𝑋 {𝑥 ∈ 𝐴 ∣ 𝑝 ∈ 𝑥} ∈ Fin)) |
3 | 2 | ibi 266 | . . 3 ⊢ (𝐴 ∈ PtFin → ∀𝑝 ∈ 𝑋 {𝑥 ∈ 𝐴 ∣ 𝑝 ∈ 𝑥} ∈ Fin) |
4 | eleq1 2813 | . . . . . 6 ⊢ (𝑝 = 𝑃 → (𝑝 ∈ 𝑥 ↔ 𝑃 ∈ 𝑥)) | |
5 | 4 | rabbidv 3426 | . . . . 5 ⊢ (𝑝 = 𝑃 → {𝑥 ∈ 𝐴 ∣ 𝑝 ∈ 𝑥} = {𝑥 ∈ 𝐴 ∣ 𝑃 ∈ 𝑥}) |
6 | 5 | eleq1d 2810 | . . . 4 ⊢ (𝑝 = 𝑃 → ({𝑥 ∈ 𝐴 ∣ 𝑝 ∈ 𝑥} ∈ Fin ↔ {𝑥 ∈ 𝐴 ∣ 𝑃 ∈ 𝑥} ∈ Fin)) |
7 | 6 | rspccv 3603 | . . 3 ⊢ (∀𝑝 ∈ 𝑋 {𝑥 ∈ 𝐴 ∣ 𝑝 ∈ 𝑥} ∈ Fin → (𝑃 ∈ 𝑋 → {𝑥 ∈ 𝐴 ∣ 𝑃 ∈ 𝑥} ∈ Fin)) |
8 | 3, 7 | syl 17 | . 2 ⊢ (𝐴 ∈ PtFin → (𝑃 ∈ 𝑋 → {𝑥 ∈ 𝐴 ∣ 𝑃 ∈ 𝑥} ∈ Fin)) |
9 | 8 | imp 405 | 1 ⊢ ((𝐴 ∈ PtFin ∧ 𝑃 ∈ 𝑋) → {𝑥 ∈ 𝐴 ∣ 𝑃 ∈ 𝑥} ∈ Fin) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 394 = wceq 1533 ∈ wcel 2098 ∀wral 3050 {crab 3418 ∪ cuni 4909 Fincfn 8964 PtFincptfin 23451 |
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-ext 2696 |
This theorem depends on definitions: df-bi 206 df-an 395 df-tru 1536 df-ex 1774 df-sb 2060 df-clab 2703 df-cleq 2717 df-clel 2802 df-ral 3051 df-rab 3419 df-v 3463 df-ss 3961 df-uni 4910 df-ptfin 23454 |
This theorem is referenced by: locfindis 23478 comppfsc 23480 |
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