Theorem fincmp 21101

Description: A finite topology is compact. (Contributed by FL, 22-Dec-2008.)

Assertion

Ref	Expression
fincmp	⊢ (𝐽 ∈ (Top ∩ Fin) → 𝐽 ∈ Comp)

Proof of Theorem fincmp

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

Step	Hyp	Ref	Expression
1		inss1 3816	. . 3 ⊢ (Top ∩ Fin) ⊆ Top
2	1	sseli 3584	. 2 ⊢ (𝐽 ∈ (Top ∩ Fin) → 𝐽 ∈ Top)
3		inss2 3817	. . . 4 ⊢ (Top ∩ Fin) ⊆ Fin
4	3	sseli 3584	. . 3 ⊢ (𝐽 ∈ (Top ∩ Fin) → 𝐽 ∈ Fin)
5		vex 3194	. . . . . 6 ⊢ 𝑦 ∈ V
6	5	pwid 4150	. . . . 5 ⊢ 𝑦 ∈ 𝒫 𝑦
7		selpw 4142	. . . . . 6 ⊢ (𝑦 ∈ 𝒫 𝐽 ↔ 𝑦 ⊆ 𝐽)
8		ssfi 8125	. . . . . 6 ⊢ ((𝐽 ∈ Fin ∧ 𝑦 ⊆ 𝐽) → 𝑦 ∈ Fin)
9	7, 8	sylan2b 492	. . . . 5 ⊢ ((𝐽 ∈ Fin ∧ 𝑦 ∈ 𝒫 𝐽) → 𝑦 ∈ Fin)
10		elin 3779	. . . . . 6 ⊢ (𝑦 ∈ (𝒫 𝑦 ∩ Fin) ↔ (𝑦 ∈ 𝒫 𝑦 ∧ 𝑦 ∈ Fin))
11		unieq 4415	. . . . . . . . 9 ⊢ (𝑧 = 𝑦 → ∪ 𝑧 = ∪ 𝑦)
12	11	eqeq2d 2636	. . . . . . . 8 ⊢ (𝑧 = 𝑦 → (∪ 𝐽 = ∪ 𝑧 ↔ ∪ 𝐽 = ∪ 𝑦))
13	12	rspcev 3300	. . . . . . 7 ⊢ ((𝑦 ∈ (𝒫 𝑦 ∩ Fin) ∧ ∪ 𝐽 = ∪ 𝑦) → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧)
14	13	ex 450	. . . . . 6 ⊢ (𝑦 ∈ (𝒫 𝑦 ∩ Fin) → (∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
15	10, 14	sylbir 225	. . . . 5 ⊢ ((𝑦 ∈ 𝒫 𝑦 ∧ 𝑦 ∈ Fin) → (∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
16	6, 9, 15	sylancr 694	. . . 4 ⊢ ((𝐽 ∈ Fin ∧ 𝑦 ∈ 𝒫 𝐽) → (∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
17	16	ralrimiva 2965	. . 3 ⊢ (𝐽 ∈ Fin → ∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
18	4, 17	syl 17	. 2 ⊢ (𝐽 ∈ (Top ∩ Fin) → ∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧))
19		eqid 2626	. . 3 ⊢ ∪ 𝐽 = ∪ 𝐽
20	19	iscmp 21096	. 2 ⊢ (𝐽 ∈ Comp ↔ (𝐽 ∈ Top ∧ ∀𝑦 ∈ 𝒫 𝐽(∪ 𝐽 = ∪ 𝑦 → ∃𝑧 ∈ (𝒫 𝑦 ∩ Fin)∪ 𝐽 = ∪ 𝑧)))
21	2, 18, 20	sylanbrc 697	1 ⊢ (𝐽 ∈ (Top ∩ Fin) → 𝐽 ∈ Comp)

Syntax hints:   → wi 4   ∧ wa 384   = wceq 1480   ∈ wcel 1992  ∀wral 2912  ∃wrex 2913   ∩ cin 3559   ⊆ wss 3560  𝒫 cpw 4135  ∪ cuni 4407  Fincfn 7900  Topctop 20612  Compccmp 21094

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1841  ax-6 1890  ax-7 1937  ax-8 1994  ax-9 2001  ax-10 2021  ax-11 2036  ax-12 2049  ax-13 2250  ax-ext 2606  ax-sep 4746  ax-nul 4754  ax-pow 4808  ax-pr 4872  ax-un 6903

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1037  df-3an 1038  df-tru 1483  df-ex 1702  df-nf 1707  df-sb 1883  df-eu 2478  df-mo 2479  df-clab 2613  df-cleq 2619  df-clel 2622  df-nfc 2756  df-ne 2797  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3193  df-sbc 3423  df-dif 3563  df-un 3565  df-in 3567  df-ss 3574  df-pss 3576  df-nul 3897  df-if 4064  df-pw 4137  df-sn 4154  df-pr 4156  df-tp 4158  df-op 4160  df-uni 4408  df-br 4619  df-opab 4679  df-tr 4718  df-eprel 4990  df-id 4994  df-po 5000  df-so 5001  df-fr 5038  df-we 5040  df-xp 5085  df-rel 5086  df-cnv 5087  df-co 5088  df-dm 5089  df-rn 5090  df-res 5091  df-ima 5092  df-ord 5688  df-on 5689  df-lim 5690  df-suc 5691  df-fun 5852  df-fn 5853  df-f 5854  df-f1 5855  df-fo 5856  df-f1o 5857  df-om 7014  df-er 7688  df-en 7901  df-fin 7904  df-cmp 21095

This theorem is referenced by:  0cmp  21102  discmp  21106  1stckgenlem  21261  ptcmpfi  21521  kelac2lem  37100