Theorem fmucnd 24517

Description: The image of a Cauchy filter base by an uniformly continuous function is a Cauchy filter base. Deduction form. Proposition 3 of [BourbakiTop1] p. II.13. (Contributed by Thierry Arnoux, 18-Nov-2017.)

Hypotheses

Ref	Expression
fmucnd.1	⊢ (𝜑 → 𝑈 ∈ (UnifOn‘𝑋))
fmucnd.2	⊢ (𝜑 → 𝑉 ∈ (UnifOn‘𝑌))
fmucnd.3	⊢ (𝜑 → 𝐹 ∈ (𝑈 Cnu𝑉))
fmucnd.4	⊢ (𝜑 → 𝐶 ∈ (CauFilu‘𝑈))
fmucnd.5	⊢ 𝐷 = ran (𝑎 ∈ 𝐶 ↦ (𝐹 “ 𝑎))

Assertion

Ref	Expression
fmucnd	⊢ (𝜑 → 𝐷 ∈ (CauFilu‘𝑉))

Distinct variable groups:   𝐶,𝑎   𝐷,𝑎   𝐹,𝑎   𝑉,𝑎   𝑋,𝑎   𝑌,𝑎   𝜑,𝑎

Allowed substitution hint:   𝑈(𝑎)

Proof of Theorem fmucnd

Dummy variables 𝑐 𝑏 𝑣 𝑟 𝑠 𝑡 𝑥 𝑦 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		fmucnd.1	. . . 4 ⊢ (𝜑 → 𝑈 ∈ (UnifOn‘𝑋))
2		fmucnd.4	. . . 4 ⊢ (𝜑 → 𝐶 ∈ (CauFilu‘𝑈))
3		cfilufbas 24514	. . . 4 ⊢ ((𝑈 ∈ (UnifOn‘𝑋) ∧ 𝐶 ∈ (CauFilu‘𝑈)) → 𝐶 ∈ (fBas‘𝑋))
4	1, 2, 3	syl2anc 596	. . 3 ⊢ (𝜑 → 𝐶 ∈ (fBas‘𝑋))
5		fmucnd.2	. . . 4 ⊢ (𝜑 → 𝑉 ∈ (UnifOn‘𝑌))
6		fmucnd.3	. . . 4 ⊢ (𝜑 → 𝐹 ∈ (𝑈 Cnu𝑉))
7		isucn 24503	. . . . 5 ⊢ ((𝑈 ∈ (UnifOn‘𝑋) ∧ 𝑉 ∈ (UnifOn‘𝑌)) → (𝐹 ∈ (𝑈 Cnu𝑉) ↔ (𝐹:𝑋⟶𝑌 ∧ ∀𝑣 ∈ 𝑉 ∃𝑟 ∈ 𝑈 ∀𝑥 ∈ 𝑋 ∀𝑦 ∈ 𝑋 (𝑥𝑟𝑦 → (𝐹‘𝑥)𝑣(𝐹‘𝑦)))))
8	7	simprbda 504	. . . 4 ⊢ (((𝑈 ∈ (UnifOn‘𝑋) ∧ 𝑉 ∈ (UnifOn‘𝑌)) ∧ 𝐹 ∈ (𝑈 Cnu𝑉)) → 𝐹:𝑋⟶𝑌)
9	1, 5, 6, 8	syl21anc 851	. . 3 ⊢ (𝜑 → 𝐹:𝑋⟶𝑌)
10	5	elfvexd 6914	. . 3 ⊢ (𝜑 → 𝑌 ∈ V)
11		fmucnd.5	. . . 4 ⊢ 𝐷 = ran (𝑎 ∈ 𝐶 ↦ (𝐹 “ 𝑎))
12	11	fbasrn 24110	. . 3 ⊢ ((𝐶 ∈ (fBas‘𝑋) ∧ 𝐹:𝑋⟶𝑌 ∧ 𝑌 ∈ V) → 𝐷 ∈ (fBas‘𝑌))
13	4, 9, 10, 12	syl3anc 1398	. 2 ⊢ (𝜑 → 𝐷 ∈ (fBas‘𝑌))
14		simplr 781	. . . . . . . 8 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → 𝑎 ∈ 𝐶)
15		eqid 2760	. . . . . . . 8 ⊢ (𝐹 “ 𝑎) = (𝐹 “ 𝑎)
16		imaeq2 6052	. . . . . . . . 9 ⊢ (𝑐 = 𝑎 → (𝐹 “ 𝑐) = (𝐹 “ 𝑎))
17	16	rspceeqv 3599	. . . . . . . 8 ⊢ ((𝑎 ∈ 𝐶 ∧ (𝐹 “ 𝑎) = (𝐹 “ 𝑎)) → ∃𝑐 ∈ 𝐶 (𝐹 “ 𝑎) = (𝐹 “ 𝑐))
18	14, 15, 17	sylancl 598	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ∃𝑐 ∈ 𝐶 (𝐹 “ 𝑎) = (𝐹 “ 𝑐))
19		imaexg 7910	. . . . . . . . 9 ⊢ (𝐹 ∈ (𝑈 Cnu𝑉) → (𝐹 “ 𝑎) ∈ V)
20		eqid 2760	. . . . . . . . . 10 ⊢ (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐)) = (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐))
21	20	elrnmpt 5942	. . . . . . . . 9 ⊢ ((𝐹 “ 𝑎) ∈ V → ((𝐹 “ 𝑎) ∈ ran (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐)) ↔ ∃𝑐 ∈ 𝐶 (𝐹 “ 𝑎) = (𝐹 “ 𝑐)))
22	6, 19, 21	3syl 19	. . . . . . . 8 ⊢ (𝜑 → ((𝐹 “ 𝑎) ∈ ran (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐)) ↔ ∃𝑐 ∈ 𝐶 (𝐹 “ 𝑎) = (𝐹 “ 𝑐)))
23	22	ad3antrrr 743	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ((𝐹 “ 𝑎) ∈ ran (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐)) ↔ ∃𝑐 ∈ 𝐶 (𝐹 “ 𝑎) = (𝐹 “ 𝑐)))
24	18, 23	mpbird 260	. . . . . 6 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → (𝐹 “ 𝑎) ∈ ran (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐)))
25		imaeq2 6052	. . . . . . . . 9 ⊢ (𝑎 = 𝑐 → (𝐹 “ 𝑎) = (𝐹 “ 𝑐))
26	25	cbvmptv 5209	. . . . . . . 8 ⊢ (𝑎 ∈ 𝐶 ↦ (𝐹 “ 𝑎)) = (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐))
27	26	rneqi 5921	. . . . . . 7 ⊢ ran (𝑎 ∈ 𝐶 ↦ (𝐹 “ 𝑎)) = ran (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐))
28	11, 27	eqtri 2783	. . . . . 6 ⊢ 𝐷 = ran (𝑐 ∈ 𝐶 ↦ (𝐹 “ 𝑐))
29	24, 28	eleqtrrdi 2871	. . . . 5 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → (𝐹 “ 𝑎) ∈ 𝐷)
30	9	ffnd 6703	. . . . . . . 8 ⊢ (𝜑 → 𝐹 Fn 𝑋)
31	30	ad3antrrr 743	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → 𝐹 Fn 𝑋)
32		fbelss 24059	. . . . . . . . 9 ⊢ ((𝐶 ∈ (fBas‘𝑋) ∧ 𝑎 ∈ 𝐶) → 𝑎 ⊆ 𝑋)
33	4, 32	sylan 592	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑎 ∈ 𝐶) → 𝑎 ⊆ 𝑋)
34	33	ad4ant13 764	. . . . . . 7 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → 𝑎 ⊆ 𝑋)
35		fmucndlem 24516	. . . . . . 7 ⊢ ((𝐹 Fn 𝑋 ∧ 𝑎 ⊆ 𝑋) → ((𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ (𝑎 × 𝑎)) = ((𝐹 “ 𝑎) × (𝐹 “ 𝑎)))
36	31, 34, 35	syl2anc 596	. . . . . 6 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ((𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ (𝑎 × 𝑎)) = ((𝐹 “ 𝑎) × (𝐹 “ 𝑎)))
37		eqid 2760	. . . . . . . . 9 ⊢ (𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) = (𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩)
38	37	mpofun 7537	. . . . . . . 8 ⊢ Fun (𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩)
39		funimass2 6616	. . . . . . . 8 ⊢ ((Fun (𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ((𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ (𝑎 × 𝑎)) ⊆ 𝑣)
40	38, 39	mpan 703	. . . . . . 7 ⊢ ((𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣) → ((𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ (𝑎 × 𝑎)) ⊆ 𝑣)
41	40	adantl 487	. . . . . 6 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ((𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ (𝑎 × 𝑎)) ⊆ 𝑣)
42	36, 41	eqsstrrd 3966	. . . . 5 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ((𝐹 “ 𝑎) × (𝐹 “ 𝑎)) ⊆ 𝑣)
43		id 23	. . . . . . . 8 ⊢ (𝑏 = (𝐹 “ 𝑎) → 𝑏 = (𝐹 “ 𝑎))
44	43	sqxpeqd 5687	. . . . . . 7 ⊢ (𝑏 = (𝐹 “ 𝑎) → (𝑏 × 𝑏) = ((𝐹 “ 𝑎) × (𝐹 “ 𝑎)))
45	44	sseq1d 3962	. . . . . 6 ⊢ (𝑏 = (𝐹 “ 𝑎) → ((𝑏 × 𝑏) ⊆ 𝑣 ↔ ((𝐹 “ 𝑎) × (𝐹 “ 𝑎)) ⊆ 𝑣))
46	45	rspcev 3576	. . . . 5 ⊢ (((𝐹 “ 𝑎) ∈ 𝐷 ∧ ((𝐹 “ 𝑎) × (𝐹 “ 𝑎)) ⊆ 𝑣) → ∃𝑏 ∈ 𝐷 (𝑏 × 𝑏) ⊆ 𝑣)
47	29, 42, 46	syl2anc 596	. . . 4 ⊢ ((((𝜑 ∧ 𝑣 ∈ 𝑉) ∧ 𝑎 ∈ 𝐶) ∧ (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣)) → ∃𝑏 ∈ 𝐷 (𝑏 × 𝑏) ⊆ 𝑣)
48	1	adantr 486	. . . . 5 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → 𝑈 ∈ (UnifOn‘𝑋))
49	2	adantr 486	. . . . 5 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → 𝐶 ∈ (CauFilu‘𝑈))
50	5	adantr 486	. . . . . 6 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → 𝑉 ∈ (UnifOn‘𝑌))
51	6	adantr 486	. . . . . 6 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → 𝐹 ∈ (𝑈 Cnu𝑉))
52		simpr 490	. . . . . 6 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → 𝑣 ∈ 𝑉)
53		nfcv 2922	. . . . . . 7 ⊢ Ⅎ𝑠⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩
54		nfcv 2922	. . . . . . 7 ⊢ Ⅎ𝑡⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩
55		nfcv 2922	. . . . . . 7 ⊢ Ⅎ𝑥⟨(𝐹‘𝑠), (𝐹‘𝑡)⟩
56		nfcv 2922	. . . . . . 7 ⊢ Ⅎ𝑦⟨(𝐹‘𝑠), (𝐹‘𝑡)⟩
57		simpl 488	. . . . . . . . 9 ⊢ ((𝑥 = 𝑠 ∧ 𝑦 = 𝑡) → 𝑥 = 𝑠)
58	57	fveq2d 6882	. . . . . . . 8 ⊢ ((𝑥 = 𝑠 ∧ 𝑦 = 𝑡) → (𝐹‘𝑥) = (𝐹‘𝑠))
59		simpr 490	. . . . . . . . 9 ⊢ ((𝑥 = 𝑠 ∧ 𝑦 = 𝑡) → 𝑦 = 𝑡)
60	59	fveq2d 6882	. . . . . . . 8 ⊢ ((𝑥 = 𝑠 ∧ 𝑦 = 𝑡) → (𝐹‘𝑦) = (𝐹‘𝑡))
61	58, 60	opeq12d 4841	. . . . . . 7 ⊢ ((𝑥 = 𝑠 ∧ 𝑦 = 𝑡) → ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩ = ⟨(𝐹‘𝑠), (𝐹‘𝑡)⟩)
62	53, 54, 55, 56, 61	cbvmpo 7507	. . . . . 6 ⊢ (𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) = (𝑠 ∈ 𝑋, 𝑡 ∈ 𝑋 ↦ ⟨(𝐹‘𝑠), (𝐹‘𝑡)⟩)
63	48, 50, 51, 52, 62	ucnprima 24507	. . . . 5 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣) ∈ 𝑈)
64		cfiluexsm 24515	. . . . 5 ⊢ ((𝑈 ∈ (UnifOn‘𝑋) ∧ 𝐶 ∈ (CauFilu‘𝑈) ∧ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣) ∈ 𝑈) → ∃𝑎 ∈ 𝐶 (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣))
65	48, 49, 63, 64	syl3anc 1398	. . . 4 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → ∃𝑎 ∈ 𝐶 (𝑎 × 𝑎) ⊆ (◡(𝑥 ∈ 𝑋, 𝑦 ∈ 𝑋 ↦ ⟨(𝐹‘𝑥), (𝐹‘𝑦)⟩) “ 𝑣))
66	47, 65	r19.29a 3170	. . 3 ⊢ ((𝜑 ∧ 𝑣 ∈ 𝑉) → ∃𝑏 ∈ 𝐷 (𝑏 × 𝑏) ⊆ 𝑣)
67	66	ralrimiva 3154	. 2 ⊢ (𝜑 → ∀𝑣 ∈ 𝑉 ∃𝑏 ∈ 𝐷 (𝑏 × 𝑏) ⊆ 𝑣)
68		iscfilu 24513	. . 3 ⊢ (𝑉 ∈ (UnifOn‘𝑌) → (𝐷 ∈ (CauFilu‘𝑉) ↔ (𝐷 ∈ (fBas‘𝑌) ∧ ∀𝑣 ∈ 𝑉 ∃𝑏 ∈ 𝐷 (𝑏 × 𝑏) ⊆ 𝑣)))
69	5, 68	syl 18	. 2 ⊢ (𝜑 → (𝐷 ∈ (CauFilu‘𝑉) ↔ (𝐷 ∈ (fBas‘𝑌) ∧ ∀𝑣 ∈ 𝑉 ∃𝑏 ∈ 𝐷 (𝑏 × 𝑏) ⊆ 𝑣)))
70	13, 67, 69	mpbir2and 726	1 ⊢ (𝜑 → 𝐷 ∈ (CauFilu‘𝑉))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1570   ∈ wcel 2145  ∀wral 3076  ∃wrex 3086  Vcvv 3450   ⊆ wss 3899  ⟨cop 4590   class class class wbr 5103   ↦ cmpt 5186   × cxp 5653  ^◡ccnv 5654  ran crn 5656   “ cima 5658  Fun wfun 6527   Fn wfn 6528  ⟶wf 6529  ‘cfv 6533  (class class class)co 7413   ∈ cmpo 7415  fBascfbas 21573  UnifOncust 24426   Cn_ucucn 24500  CauFil_uccfilu 24511

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 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-11 2194  ax-12 2213  ax-ext 2732  ax-rep 5232  ax-sep 5251  ax-nul 5263  ax-pow 5330  ax-pr 5398  ax-un 7736

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 2100  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ne 2956  df-nel 3062  df-ral 3077  df-rex 3087  df-rab 3413  df-v 3452  df-sbc 3740  df-csb 3848  df-dif 3902  df-un 3904  df-in 3906  df-ss 3916  df-nul 4280  df-if 4483  df-pw 4559  df-sn 4585  df-pr 4587  df-op 4591  df-uni 4868  df-iun 4953  df-br 5104  df-opab 5168  df-mpt 5187  df-id 5550  df-xp 5661  df-rel 5662  df-cnv 5663  df-co 5664  df-dm 5665  df-rn 5666  df-res 5667  df-ima 5668  df-iota 6489  df-fun 6535  df-fn 6536  df-f 6537  df-fv 6541  df-ov 7416  df-oprab 7417  df-mpo 7418  df-1st 7986  df-2nd 7987  df-map 8828  df-fbas 21582  df-ust 24427  df-ucn 24501  df-cfilu 24512

This theorem is used by:  ucnextcn  24529