Theorem opnfbas 24205

Description: The collection of open supersets of a nonempty set in a topology is a neighborhoods of the set, one of the motivations for the filter concept. (Contributed by Jeff Hankins, 2-Sep-2009.) (Revised by Mario Carneiro, 7-Aug-2015.)

Hypothesis

Ref	Expression
opnfbas.1	⊢ 𝑋 = ∪ 𝐽

Assertion

Ref	Expression
opnfbas	⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∈ (fBas‘𝑋))

Distinct variable groups:   𝑥,𝐽   𝑥,𝑆   𝑥,𝑋

Proof of Theorem opnfbas

Dummy variables 𝑠 𝑟 𝑡 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		ssrab2 4008	. . . 4 ⊢ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ⊆ 𝐽
2		opnfbas.1	. . . . . 6 ⊢ 𝑋 = ∪ 𝐽
3	2	eqimss2i 3974	. . . . 5 ⊢ ∪ 𝐽 ⊆ 𝑋
4		sspwuni 5063	. . . . 5 ⊢ (𝐽 ⊆ 𝒫 𝑋 ↔ ∪ 𝐽 ⊆ 𝑋)
5	3, 4	mpbir 234	. . . 4 ⊢ 𝐽 ⊆ 𝒫 𝑋
6	1, 5	sstri 3922	. . 3 ⊢ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ⊆ 𝒫 𝑋
7	6	a1i 11	. 2 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ⊆ 𝒫 𝑋)
8	2	topopn 23268	. . . . . . 7 ⊢ (𝐽 ∈ Top → 𝑋 ∈ 𝐽)
9	8	anim1i 627	. . . . . 6 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋) → (𝑋 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑋))
10	9	3adant3 1150	. . . . 5 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → (𝑋 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑋))
11		sseq2 3939	. . . . . 6 ⊢ (𝑥 = 𝑋 → (𝑆 ⊆ 𝑥 ↔ 𝑆 ⊆ 𝑋))
12	11	elrab 3648	. . . . 5 ⊢ (𝑋 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ (𝑋 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑋))
13	10, 12	sylibr 237	. . . 4 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → 𝑋 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥})
14	13	ne0d 4291	. . 3 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ≠ ∅)
15		ss0 4355	. . . . . . 7 ⊢ (𝑆 ⊆ ∅ → 𝑆 = ∅)
16	15	necon3ai 2984	. . . . . 6 ⊢ (𝑆 ≠ ∅ → ¬ 𝑆 ⊆ ∅)
17	16	3ad2ant3 1153	. . . . 5 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ¬ 𝑆 ⊆ ∅)
18	17	intnand 494	. . . 4 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ¬ (∅ ∈ 𝐽 ∧ 𝑆 ⊆ ∅))
19		df-nel 3066	. . . . 5 ⊢ (∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ ¬ ∅ ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥})
20		sseq2 3939	. . . . . . 7 ⊢ (𝑥 = ∅ → (𝑆 ⊆ 𝑥 ↔ 𝑆 ⊆ ∅))
21	20	elrab 3648	. . . . . 6 ⊢ (∅ ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ (∅ ∈ 𝐽 ∧ 𝑆 ⊆ ∅))
22	21	notbii 323	. . . . 5 ⊢ (¬ ∅ ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ ¬ (∅ ∈ 𝐽 ∧ 𝑆 ⊆ ∅))
23	19, 22	bitr2i 279	. . . 4 ⊢ (¬ (∅ ∈ 𝐽 ∧ 𝑆 ⊆ ∅) ↔ ∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥})
24	18, 23	sylib 221	. . 3 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥})
25		sseq2 3939	. . . . . . 7 ⊢ (𝑥 = 𝑟 → (𝑆 ⊆ 𝑥 ↔ 𝑆 ⊆ 𝑟))
26	25	elrab 3648	. . . . . 6 ⊢ (𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ (𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟))
27		sseq2 3939	. . . . . . 7 ⊢ (𝑥 = 𝑠 → (𝑆 ⊆ 𝑥 ↔ 𝑆 ⊆ 𝑠))
28	27	elrab 3648	. . . . . 6 ⊢ (𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))
29	26, 28	anbi12i 640	. . . . 5 ⊢ ((𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ 𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}) ↔ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠)))
30		simpl 488	. . . . . . . . . . 11 ⊢ ((𝐽 ∈ Top ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → 𝐽 ∈ Top)
31		simprll 791	. . . . . . . . . . 11 ⊢ ((𝐽 ∈ Top ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → 𝑟 ∈ 𝐽)
32		simprrl 793	. . . . . . . . . . 11 ⊢ ((𝐽 ∈ Top ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → 𝑠 ∈ 𝐽)
33		inopn 23261	. . . . . . . . . . 11 ⊢ ((𝐽 ∈ Top ∧ 𝑟 ∈ 𝐽 ∧ 𝑠 ∈ 𝐽) → (𝑟 ∩ 𝑠) ∈ 𝐽)
34	30, 31, 32, 33	syl3anc 1399	. . . . . . . . . 10 ⊢ ((𝐽 ∈ Top ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → (𝑟 ∩ 𝑠) ∈ 𝐽)
35		ssin 4138	. . . . . . . . . . . . 13 ⊢ ((𝑆 ⊆ 𝑟 ∧ 𝑆 ⊆ 𝑠) ↔ 𝑆 ⊆ (𝑟 ∩ 𝑠))
36	35	biimpi 219	. . . . . . . . . . . 12 ⊢ ((𝑆 ⊆ 𝑟 ∧ 𝑆 ⊆ 𝑠) → 𝑆 ⊆ (𝑟 ∩ 𝑠))
37	36	ad2ant2l 759	. . . . . . . . . . 11 ⊢ (((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠)) → 𝑆 ⊆ (𝑟 ∩ 𝑠))
38	37	adantl 487	. . . . . . . . . 10 ⊢ ((𝐽 ∈ Top ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → 𝑆 ⊆ (𝑟 ∩ 𝑠))
39	34, 38	jca 521	. . . . . . . . 9 ⊢ ((𝐽 ∈ Top ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → ((𝑟 ∩ 𝑠) ∈ 𝐽 ∧ 𝑆 ⊆ (𝑟 ∩ 𝑠)))
40	39	3ad2antl1 1204	. . . . . . . 8 ⊢ (((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → ((𝑟 ∩ 𝑠) ∈ 𝐽 ∧ 𝑆 ⊆ (𝑟 ∩ 𝑠)))
41		sseq2 3939	. . . . . . . . 9 ⊢ (𝑥 = (𝑟 ∩ 𝑠) → (𝑆 ⊆ 𝑥 ↔ 𝑆 ⊆ (𝑟 ∩ 𝑠)))
42	41	elrab 3648	. . . . . . . 8 ⊢ ((𝑟 ∩ 𝑠) ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ↔ ((𝑟 ∩ 𝑠) ∈ 𝐽 ∧ 𝑆 ⊆ (𝑟 ∩ 𝑠)))
43	40, 42	sylibr 237	. . . . . . 7 ⊢ (((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → (𝑟 ∩ 𝑠) ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥})
44		ssid 3935	. . . . . . 7 ⊢ (𝑟 ∩ 𝑠) ⊆ (𝑟 ∩ 𝑠)
45		sseq1 3938	. . . . . . . 8 ⊢ (𝑡 = (𝑟 ∩ 𝑠) → (𝑡 ⊆ (𝑟 ∩ 𝑠) ↔ (𝑟 ∩ 𝑠) ⊆ (𝑟 ∩ 𝑠)))
46	45	rspcev 3580	. . . . . . 7 ⊢ (((𝑟 ∩ 𝑠) ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ (𝑟 ∩ 𝑠) ⊆ (𝑟 ∩ 𝑠)) → ∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠))
47	43, 44, 46	sylancl 598	. . . . . 6 ⊢ (((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) ∧ ((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠))) → ∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠))
48	47	ex 418	. . . . 5 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → (((𝑟 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑟) ∧ (𝑠 ∈ 𝐽 ∧ 𝑆 ⊆ 𝑠)) → ∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠)))
49	29, 48	biimtrid 245	. . . 4 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ((𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ 𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}) → ∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠)))
50	49	ralrimivv 3207	. . 3 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ∀𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∀𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠))
51	14, 24, 50	3jca 1146	. 2 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ≠ ∅ ∧ ∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ ∀𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∀𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠)))
52		isfbas2 24198	. . . 4 ⊢ (𝑋 ∈ 𝐽 → ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∈ (fBas‘𝑋) ↔ ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ⊆ 𝒫 𝑋 ∧ ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ≠ ∅ ∧ ∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ ∀𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∀𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠)))))
53	8, 52	syl 18	. . 3 ⊢ (𝐽 ∈ Top → ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∈ (fBas‘𝑋) ↔ ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ⊆ 𝒫 𝑋 ∧ ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ≠ ∅ ∧ ∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ ∀𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∀𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠)))))
54	53	3ad2ant1 1151	. 2 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∈ (fBas‘𝑋) ↔ ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ⊆ 𝒫 𝑋 ∧ ({𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ≠ ∅ ∧ ∅ ∉ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∧ ∀𝑟 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∀𝑠 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}∃𝑡 ∈ {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥}𝑡 ⊆ (𝑟 ∩ 𝑠)))))
55	7, 51, 54	mpbir2and 726	1 ⊢ ((𝐽 ∈ Top ∧ 𝑆 ⊆ 𝑋 ∧ 𝑆 ≠ ∅) → {𝑥 ∈ 𝐽 ∣ 𝑆 ⊆ 𝑥} ∈ (fBas‘𝑋))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 401   ∧ w3a 1103   = wceq 1570   ∈ wcel 2147   ≠ wne 2959   ∉ wnel 3065  ∀wral 3080  ∃wrex 3090  {crab 3416   ⊆ wss 3900   ∩ cin 4092  ∅c0 4281  𝒫 cpw 4560  ∪ cuni 4870  ‘cfv 6564  fBascfbas 21708  Topctop 23255

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1945  ax-6 2002  ax-7 2043  ax-8 2149  ax-9 2157  ax-10 2180  ax-11 2197  ax-12 2216  ax-ext 2735  ax-sep 5253  ax-nul 5264  ax-pow 5332  ax-pr 5396

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2102  df-mo 2567  df-eu 2597  df-clab 2742  df-cleq 2755  df-clel 2839  df-nfc 2913  df-ne 2960  df-nel 3066  df-ral 3081  df-rex 3091  df-rab 3417  df-v 3456  df-sbc 3743  df-csb 3852  df-ss 3901  df-dif 4050  df-in 4094  df-un 4154  df-nul 4282  df-if 4486  df-pw 4562  df-sn 4589  df-pr 4591  df-op 4839  df-uni 4871  df-br 5107  df-opab 5172  df-mpt 5191  df-id 5551  df-xp 5662  df-rel 5663  df-cnv 5664  df-co 5665  df-dm 5666  df-rn 5667  df-res 5668  df-ima 5669  df-iota 6518  df-fun 6566  df-fv 6572  df-fbas 21717  df-top 23256

This theorem is used by:  neifg  37367