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| Mirrors > Home > MPE Home > Th. List > Mathboxes > df-pcmp | Structured version Visualization version GIF version | ||
| Description: Definition of a paracompact topology. A topology is said to be paracompact iff every open cover has an open refinement that is locally finite. The definition 6 of [BourbakiTop1] p. I.69. also requires the topology to be Hausdorff, but this is dropped here. (Contributed by Thierry Arnoux, 7-Jan-2020.) | 
| Ref | Expression | 
|---|---|
| df-pcmp | ⊢ Paracomp = {𝑗 ∣ 𝑗 ∈ CovHasRef(LocFin‘𝑗)} | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cpcmp 33854 | . 2 class Paracomp | |
| 2 | vj | . . . . 5 setvar 𝑗 | |
| 3 | 2 | cv 1539 | . . . 4 class 𝑗 | 
| 4 | clocfin 23512 | . . . . . 6 class LocFin | |
| 5 | 3, 4 | cfv 6561 | . . . . 5 class (LocFin‘𝑗) | 
| 6 | 5 | ccref 33841 | . . . 4 class CovHasRef(LocFin‘𝑗) | 
| 7 | 3, 6 | wcel 2108 | . . 3 wff 𝑗 ∈ CovHasRef(LocFin‘𝑗) | 
| 8 | 7, 2 | cab 2714 | . 2 class {𝑗 ∣ 𝑗 ∈ CovHasRef(LocFin‘𝑗)} | 
| 9 | 1, 8 | wceq 1540 | 1 wff Paracomp = {𝑗 ∣ 𝑗 ∈ CovHasRef(LocFin‘𝑗)} | 
| Colors of variables: wff setvar class | 
| This definition is referenced by: ispcmp 33856 | 
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