Theorem setrec2fun 50273

Description: This is the second of two fundamental theorems about set recursion from which all other facts will be derived. It states that the class setrecs(𝐹) is a subclass of all classes 𝐶 that are closed under 𝐹. Taken together, Theorems setrec1 50272 and setrec2v 50277 say that setrecs(𝐹) is the minimal class closed under 𝐹.

We express this by saying that if 𝐹 respects the ⊆ relation and 𝐶 is closed under 𝐹, then 𝐵 ⊆ 𝐶. By substituting strategically constructed classes for 𝐶, we can easily prove many useful properties. Although this theorem cannot show equality between 𝐵 and 𝐶, if we intend to prove equality between 𝐵 and some particular class (such as On), we first apply this theorem, then the relevant induction theorem (such as tfi 7827) to the other class. (Contributed by Emmett Weisz, 15-Feb-2021.) (New usage is discouraged.)

Hypotheses

Ref	Expression
setrec2fun.1	⊢ Ⅎ𝑎𝐹
setrec2fun.2	⊢ 𝐵 = setrecs(𝐹)
setrec2fun.3	⊢ Fun 𝐹
setrec2fun.4	⊢ (𝜑 → ∀𝑎(𝑎 ⊆ 𝐶 → (𝐹‘𝑎) ⊆ 𝐶))

Assertion

Ref	Expression
setrec2fun	⊢ (𝜑 → 𝐵 ⊆ 𝐶)

Distinct variable group:   𝐶,𝑎

Allowed substitution hints:   𝜑(𝑎)   𝐵(𝑎)   𝐹(𝑎)

Proof of Theorem setrec2fun

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

Step	Hyp	Ref	Expression
1		setrec2fun.2	. . 3 ⊢ 𝐵 = setrecs(𝐹)
2		df-setrecs 50265	. . 3 ⊢ setrecs(𝐹) = ∪ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)}
3	1, 2	eqtri 2784	. 2 ⊢ 𝐵 = ∪ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)}
4		eqid 2761	. . . . . 6 ⊢ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)} = {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)}
5		vex 3457	. . . . . . 7 ⊢ 𝑥 ∈ V
6	5	a1i 11	. . . . . 6 ⊢ (𝜑 → 𝑥 ∈ V)
7	4, 6	setrec1lem1 50268	. . . . 5 ⊢ (𝜑 → (𝑥 ∈ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)} ↔ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑥 ⊆ 𝑧)))
8		id 22	. . . . . . . . . . . . . . 15 ⊢ (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → 𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))
9		inss1 4186	. . . . . . . . . . . . . . 15 ⊢ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) ⊆ 𝐶
10	8, 9	sstrdi 3946	. . . . . . . . . . . . . 14 ⊢ (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → 𝑤 ⊆ 𝐶)
11		setrec2fun.4	. . . . . . . . . . . . . . 15 ⊢ (𝜑 → ∀𝑎(𝑎 ⊆ 𝐶 → (𝐹‘𝑎) ⊆ 𝐶))
12		nfv 1933	. . . . . . . . . . . . . . . . 17 ⊢ Ⅎ𝑎 𝑤 ⊆ 𝐶
13		setrec2fun.1	. . . . . . . . . . . . . . . . . . 19 ⊢ Ⅎ𝑎𝐹
14		nfcv 2923	. . . . . . . . . . . . . . . . . . 19 ⊢ Ⅎ𝑎𝑤
15	13, 14	nffv 6871	. . . . . . . . . . . . . . . . . 18 ⊢ Ⅎ𝑎(𝐹‘𝑤)
16		nfcv 2923	. . . . . . . . . . . . . . . . . 18 ⊢ Ⅎ𝑎𝐶
17	15, 16	nfss 3927	. . . . . . . . . . . . . . . . 17 ⊢ Ⅎ𝑎(𝐹‘𝑤) ⊆ 𝐶
18	12, 17	nfim 1915	. . . . . . . . . . . . . . . 16 ⊢ Ⅎ𝑎(𝑤 ⊆ 𝐶 → (𝐹‘𝑤) ⊆ 𝐶)
19		sseq1 3959	. . . . . . . . . . . . . . . . . 18 ⊢ (𝑎 = 𝑤 → (𝑎 ⊆ 𝐶 ↔ 𝑤 ⊆ 𝐶))
20		fveq2 6861	. . . . . . . . . . . . . . . . . . 19 ⊢ (𝑎 = 𝑤 → (𝐹‘𝑎) = (𝐹‘𝑤))
21	20	sseq1d 3965	. . . . . . . . . . . . . . . . . 18 ⊢ (𝑎 = 𝑤 → ((𝐹‘𝑎) ⊆ 𝐶 ↔ (𝐹‘𝑤) ⊆ 𝐶))
22	19, 21	imbi12d 346	. . . . . . . . . . . . . . . . 17 ⊢ (𝑎 = 𝑤 → ((𝑎 ⊆ 𝐶 → (𝐹‘𝑎) ⊆ 𝐶) ↔ (𝑤 ⊆ 𝐶 → (𝐹‘𝑤) ⊆ 𝐶)))
23	22	biimpd 231	. . . . . . . . . . . . . . . 16 ⊢ (𝑎 = 𝑤 → ((𝑎 ⊆ 𝐶 → (𝐹‘𝑎) ⊆ 𝐶) → (𝑤 ⊆ 𝐶 → (𝐹‘𝑤) ⊆ 𝐶)))
24	18, 23	spimfv 2273	. . . . . . . . . . . . . . 15 ⊢ (∀𝑎(𝑎 ⊆ 𝐶 → (𝐹‘𝑎) ⊆ 𝐶) → (𝑤 ⊆ 𝐶 → (𝐹‘𝑤) ⊆ 𝐶))
25	11, 24	syl 17	. . . . . . . . . . . . . 14 ⊢ (𝜑 → (𝑤 ⊆ 𝐶 → (𝐹‘𝑤) ⊆ 𝐶))
26	10, 25	syl5 34	. . . . . . . . . . . . 13 ⊢ (𝜑 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ 𝐶))
27	26	imp 410	. . . . . . . . . . . 12 ⊢ ((𝜑 ∧ 𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))) → (𝐹‘𝑤) ⊆ 𝐶)
28	27	3adant2 1143	. . . . . . . . . . 11 ⊢ ((𝜑 ∧ 𝑤 ⊆ 𝑥 ∧ 𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))) → (𝐹‘𝑤) ⊆ 𝐶)
29		velpw 4557	. . . . . . . . . . . . . . 15 ⊢ (𝑤 ∈ 𝒫 𝑥 ↔ 𝑤 ⊆ 𝑥)
30		eliman0 6898	. . . . . . . . . . . . . . . 16 ⊢ ((𝑤 ∈ 𝒫 𝑥 ∧ ¬ (𝐹‘𝑤) = ∅) → (𝐹‘𝑤) ∈ (𝐹 “ 𝒫 𝑥))
31	30	ex 416	. . . . . . . . . . . . . . 15 ⊢ (𝑤 ∈ 𝒫 𝑥 → (¬ (𝐹‘𝑤) = ∅ → (𝐹‘𝑤) ∈ (𝐹 “ 𝒫 𝑥)))
32	29, 31	sylbir 237	. . . . . . . . . . . . . 14 ⊢ (𝑤 ⊆ 𝑥 → (¬ (𝐹‘𝑤) = ∅ → (𝐹‘𝑤) ∈ (𝐹 “ 𝒫 𝑥)))
33		elssuni 4894	. . . . . . . . . . . . . 14 ⊢ ((𝐹‘𝑤) ∈ (𝐹 “ 𝒫 𝑥) → (𝐹‘𝑤) ⊆ ∪ (𝐹 “ 𝒫 𝑥))
34	32, 33	syl6 35	. . . . . . . . . . . . 13 ⊢ (𝑤 ⊆ 𝑥 → (¬ (𝐹‘𝑤) = ∅ → (𝐹‘𝑤) ⊆ ∪ (𝐹 “ 𝒫 𝑥)))
35		id 22	. . . . . . . . . . . . . 14 ⊢ ((𝐹‘𝑤) = ∅ → (𝐹‘𝑤) = ∅)
36		0ss 4351	. . . . . . . . . . . . . 14 ⊢ ∅ ⊆ ∪ (𝐹 “ 𝒫 𝑥)
37	35, 36	eqsstrdi 3978	. . . . . . . . . . . . 13 ⊢ ((𝐹‘𝑤) = ∅ → (𝐹‘𝑤) ⊆ ∪ (𝐹 “ 𝒫 𝑥))
38	34, 37	pm2.61d2 182	. . . . . . . . . . . 12 ⊢ (𝑤 ⊆ 𝑥 → (𝐹‘𝑤) ⊆ ∪ (𝐹 “ 𝒫 𝑥))
39	38	3ad2ant2 1146	. . . . . . . . . . 11 ⊢ ((𝜑 ∧ 𝑤 ⊆ 𝑥 ∧ 𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))) → (𝐹‘𝑤) ⊆ ∪ (𝐹 “ 𝒫 𝑥))
40	28, 39	ssind 4190	. . . . . . . . . 10 ⊢ ((𝜑 ∧ 𝑤 ⊆ 𝑥 ∧ 𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))
41	40	3exp 1131	. . . . . . . . 9 ⊢ (𝜑 → (𝑤 ⊆ 𝑥 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))))
42	41	alrimiv 1946	. . . . . . . 8 ⊢ (𝜑 → ∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))))
43		setrec2fun.3	. . . . . . . . . . . 12 ⊢ Fun 𝐹
44	5	pwex 5334	. . . . . . . . . . . . 13 ⊢ 𝒫 𝑥 ∈ V
45	44	funimaex 6603	. . . . . . . . . . . 12 ⊢ (Fun 𝐹 → (𝐹 “ 𝒫 𝑥) ∈ V)
46	43, 45	ax-mp 5	. . . . . . . . . . 11 ⊢ (𝐹 “ 𝒫 𝑥) ∈ V
47	46	uniex 7718	. . . . . . . . . 10 ⊢ ∪ (𝐹 “ 𝒫 𝑥) ∈ V
48	47	inex2 5271	. . . . . . . . 9 ⊢ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) ∈ V
49		sseq2 3960	. . . . . . . . . . . . 13 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝑤 ⊆ 𝑧 ↔ 𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))))
50		sseq2 3960	. . . . . . . . . . . . 13 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → ((𝐹‘𝑤) ⊆ 𝑧 ↔ (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))))
51	49, 50	imbi12d 346	. . . . . . . . . . . 12 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → ((𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧) ↔ (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))))
52	51	imbi2d 342	. . . . . . . . . . 11 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → ((𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) ↔ (𝑤 ⊆ 𝑥 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))))))
53	52	albidv 1939	. . . . . . . . . 10 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) ↔ ∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))))))
54		sseq2 3960	. . . . . . . . . 10 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝑥 ⊆ 𝑧 ↔ 𝑥 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))))
55	53, 54	imbi12d 346	. . . . . . . . 9 ⊢ (𝑧 = (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → ((∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑥 ⊆ 𝑧) ↔ (∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))) → 𝑥 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))))
56	48, 55	spcv 3563	. . . . . . . 8 ⊢ (∀𝑧(∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑥 ⊆ 𝑧) → (∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)) → (𝐹‘𝑤) ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))) → 𝑥 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥))))
57	42, 56	mpan9 514	. . . . . . 7 ⊢ ((𝜑 ∧ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑥 ⊆ 𝑧)) → 𝑥 ⊆ (𝐶 ∩ ∪ (𝐹 “ 𝒫 𝑥)))
58	57, 9	sstrdi 3946	. . . . . 6 ⊢ ((𝜑 ∧ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑥 ⊆ 𝑧)) → 𝑥 ⊆ 𝐶)
59	58	ex 416	. . . . 5 ⊢ (𝜑 → (∀𝑧(∀𝑤(𝑤 ⊆ 𝑥 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑥 ⊆ 𝑧) → 𝑥 ⊆ 𝐶))
60	7, 59	sylbid 242	. . . 4 ⊢ (𝜑 → (𝑥 ∈ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)} → 𝑥 ⊆ 𝐶))
61	60	ralrimiv 3152	. . 3 ⊢ (𝜑 → ∀𝑥 ∈ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)}𝑥 ⊆ 𝐶)
62		unissb 4896	. . 3 ⊢ (∪ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)} ⊆ 𝐶 ↔ ∀𝑥 ∈ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)}𝑥 ⊆ 𝐶)
63	61, 62	sylibr 236	. 2 ⊢ (𝜑 → ∪ {𝑦 ∣ ∀𝑧(∀𝑤(𝑤 ⊆ 𝑦 → (𝑤 ⊆ 𝑧 → (𝐹‘𝑤) ⊆ 𝑧)) → 𝑦 ⊆ 𝑧)} ⊆ 𝐶)
64	3, 63	eqsstrid 3972	1 ⊢ (𝜑 → 𝐵 ⊆ 𝐶)

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 399   ∧ w3a 1097  ∀wal 1557   = wceq 1559   ∈ wcel 2141  {cab 2739  Ⅎwnfc 2908  ∀wral 3075  Vcvv 3453   ∩ cin 3901   ⊆ wss 3902  ∅c0 4283  𝒫 cpw 4552  ∪ cuni 4862   “ cima 5646  Fun wfun 6509  ‘cfv 6515  setrecscsetrecs 50264

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1814  ax-4 1828  ax-5 1929  ax-6 1986  ax-7 2027  ax-8 2143  ax-9 2151  ax-10 2174  ax-11 2190  ax-12 2211  ax-ext 2733  ax-rep 5224  ax-sep 5243  ax-nul 5253  ax-pow 5319  ax-pr 5387  ax-un 7712

This theorem depends on definitions:  df-bi 209  df-an 400  df-or 859  df-3an 1099  df-tru 1562  df-fal 1572  df-ex 1799  df-nf 1803  df-sb 2090  df-mo 2565  df-eu 2595  df-clab 2740  df-cleq 2753  df-clel 2836  df-nfc 2910  df-ne 2957  df-ral 3076  df-rex 3086  df-rab 3414  df-v 3455  df-dif 3905  df-un 3907  df-in 3909  df-ss 3919  df-nul 4284  df-if 4478  df-pw 4554  df-sn 4580  df-pr 4582  df-op 4586  df-uni 4863  df-br 5098  df-opab 5160  df-id 5538  df-xp 5649  df-rel 5650  df-cnv 5651  df-co 5652  df-dm 5653  df-rn 5654  df-res 5655  df-ima 5656  df-iota 6471  df-fun 6517  df-fv 6523  df-setrecs 50265

This theorem is referenced by:  setrec2  50276