Theorem pibt1 37848

Description: Theorem T000001 of pi-base. A compact topology is also countably compact. See pibp16 37845 and pibp19 37846 for the definitions of the relevant properties. (Contributed by ML, 8-Dec-2020.)

Hypothesis

Ref	Expression
pibt1.19	⊢ 𝐶 = {𝑥 ∈ Top ∣ ∀𝑦 ∈ 𝒫 𝑥((∪ 𝑥 = ∪ 𝑦 ∧ 𝑦 ≼ ω) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝑥 = ∪ 𝑧)}

Assertion

Ref	Expression
pibt1	⊢ (𝐽 ∈ Comp → 𝐽 ∈ 𝐶)

Distinct variable group:   𝑥,𝐽,𝑦,𝑧

Allowed substitution hints:   𝐶(𝑥,𝑦,𝑧)

Proof of Theorem pibt1

Step	Hyp	Ref	Expression
1		pm3.41 495	. . . 4 ⊢ ((∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧) → ((∪ 𝐽 = ∪ 𝑦 ∧ 𝑦 ≼ ω) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
2	1	ralimi 3089	. . 3 ⊢ (∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧) → ∀𝑦 ∈ 𝒫 𝐽((∪ 𝐽 = ∪ 𝑦 ∧ 𝑦 ≼ ω) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
3	2	anim2i 625	. 2 ⊢ ((𝐽 ∈ Top ∧ ∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧)) → (𝐽 ∈ Top ∧ ∀𝑦 ∈ 𝒫 𝐽((∪ 𝐽 = ∪ 𝑦 ∧ 𝑦 ≼ ω) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧)))
4		eqid 2752	. . 3 ⊢ ∪ 𝐽 = ∪ 𝐽
5	4	pibp16 37845	. 2 ⊢ (𝐽 ∈ Comp ↔ (𝐽 ∈ Top ∧ ∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧)))
6		pibt1.19	. . 3 ⊢ 𝐶 = {𝑥 ∈ Top ∣ ∀𝑦 ∈ 𝒫 𝑥((∪ 𝑥 = ∪ 𝑦 ∧ 𝑦 ≼ ω) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝑥 = ∪ 𝑧)}
7	4, 6	pibp19 37846	. 2 ⊢ (𝐽 ∈ 𝐶 ↔ (𝐽 ∈ Top ∧ ∀𝑦 ∈ 𝒫 𝐽((∪ 𝐽 = ∪ 𝑦 ∧ 𝑦 ≼ ω) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧)))
8	3, 5, 7	3imtr4i 294	1 ⊢ (𝐽 ∈ Comp → 𝐽 ∈ 𝐶)

Syntax hints:   → wi 4   ∧ wa 398   = wceq 1550   ∈ wcel 2132  ∀wral 3066  ∃wrex 3076  {crab 3404   ∩ cin 3894  𝒫 cpw 4545  ∪ cuni 4855   class class class wbr 5090  ωcom 7831   ≼ cdom 8910  Fincfn 8912  Topctop 22922  Compccmp 23415

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1805  ax-4 1819  ax-5 1920  ax-6 1977  ax-7 2018  ax-8 2134  ax-9 2142  ax-ext 2724

This theorem depends on definitions:  df-bi 209  df-an 399  df-tru 1553  df-ex 1790  df-sb 2081  df-clab 2731  df-cleq 2744  df-clel 2827  df-ral 3067  df-rex 3077  df-rab 3405  df-v 3446  df-ss 3912  df-pw 4547  df-uni 4856  df-cmp 23416

This theorem is referenced by: (None)