Theorem creftop 34143

Description: A space where every open cover has an 𝐴 refinement is a topological space. (Contributed by Thierry Arnoux, 7-Jan-2020.)

Assertion

Ref	Expression
creftop	⊢ (𝐽 ∈ CovHasRef𝐴 → 𝐽 ∈ Top)

Proof of Theorem creftop

Dummy variables 𝑦 𝑧 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		eqid 2762	. . 3 ⊢ ∪ 𝐽 = ∪ 𝐽
2	1	iscref 34141	. 2 ⊢ (𝐽 ∈ CovHasRef𝐴 ↔ (𝐽 ∈ Top ∧ ∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝐽 ∩ 𝐴)𝑧Ref𝑦)))
3	2	simplbi 500	1 ⊢ (𝐽 ∈ CovHasRef𝐴 → 𝐽 ∈ Top)

Syntax hints:   → wi 4   = wceq 1560   ∈ wcel 2142  ∀wral 3076  ∃wrex 3086   ∩ cin 3903  𝒫 cpw 4555  ∪ cuni 4865   class class class wbr 5100  Topctop 22953  Refcref 23562  CovHasRefccref 34139

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1815  ax-4 1829  ax-5 1930  ax-6 1987  ax-7 2028  ax-8 2144  ax-9 2152  ax-ext 2734

This theorem depends on definitions:  df-bi 209  df-an 400  df-tru 1563  df-ex 1800  df-sb 2091  df-clab 2741  df-cleq 2754  df-clel 2837  df-ral 3077  df-rex 3087  df-rab 3415  df-v 3456  df-in 3911  df-ss 3921  df-pw 4557  df-uni 4866  df-cref 34140

This theorem is referenced by: (None)