Theorem ac6sfi 9058

Description: A version of ac6s 10240 for finite sets. (Contributed by Jeff Hankins, 26-Jun-2009.) (Proof shortened by Mario Carneiro, 29-Jan-2014.)

Hypothesis

Ref	Expression
ac6sfi.1	⊢ (𝑦 = (𝑓‘𝑥) → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
ac6sfi	⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑) → ∃𝑓(𝑓:𝐴⟶𝐵 ∧ ∀𝑥 ∈ 𝐴 𝜓))

Distinct variable groups:   𝑥,𝑓,𝐴   𝑦,𝑓,𝐵,𝑥   𝜑,𝑓   𝜓,𝑦

Allowed substitution hints:   𝜑(𝑥,𝑦)   𝜓(𝑥,𝑓)   𝐴(𝑦)

Proof of Theorem ac6sfi

Dummy variables 𝑢 𝑤 𝑧 𝑔 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		raleq 3342	. . . 4 ⊢ (𝑢 = ∅ → (∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑥 ∈ ∅ ∃𝑦 ∈ 𝐵 𝜑))
2		feq2 6582	. . . . . 6 ⊢ (𝑢 = ∅ → (𝑓:𝑢⟶𝐵 ↔ 𝑓:∅⟶𝐵))
3		raleq 3342	. . . . . 6 ⊢ (𝑢 = ∅ → (∀𝑥 ∈ 𝑢 𝜓 ↔ ∀𝑥 ∈ ∅ 𝜓))
4	2, 3	anbi12d 631	. . . . 5 ⊢ (𝑢 = ∅ → ((𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ (𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓)))
5	4	exbidv 1924	. . . 4 ⊢ (𝑢 = ∅ → (∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ ∃𝑓(𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓)))
6	1, 5	imbi12d 345	. . 3 ⊢ (𝑢 = ∅ → ((∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓)) ↔ (∀𝑥 ∈ ∅ ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓))))
7		raleq 3342	. . . 4 ⊢ (𝑢 = 𝑤 → (∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑))
8		feq2 6582	. . . . . 6 ⊢ (𝑢 = 𝑤 → (𝑓:𝑢⟶𝐵 ↔ 𝑓:𝑤⟶𝐵))
9		raleq 3342	. . . . . 6 ⊢ (𝑢 = 𝑤 → (∀𝑥 ∈ 𝑢 𝜓 ↔ ∀𝑥 ∈ 𝑤 𝜓))
10	8, 9	anbi12d 631	. . . . 5 ⊢ (𝑢 = 𝑤 → ((𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)))
11	10	exbidv 1924	. . . 4 ⊢ (𝑢 = 𝑤 → (∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)))
12	7, 11	imbi12d 345	. . 3 ⊢ (𝑢 = 𝑤 → ((∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓)) ↔ (∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓))))
13		raleq 3342	. . . 4 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → (∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑))
14		feq2 6582	. . . . . . 7 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → (𝑓:𝑢⟶𝐵 ↔ 𝑓:(𝑤 ∪ {𝑧})⟶𝐵))
15		raleq 3342	. . . . . . 7 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → (∀𝑥 ∈ 𝑢 𝜓 ↔ ∀𝑥 ∈ (𝑤 ∪ {𝑧})𝜓))
16	14, 15	anbi12d 631	. . . . . 6 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → ((𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ (𝑓:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})𝜓)))
17	16	exbidv 1924	. . . . 5 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → (∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ ∃𝑓(𝑓:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})𝜓)))
18		feq1 6581	. . . . . . 7 ⊢ (𝑓 = 𝑔 → (𝑓:(𝑤 ∪ {𝑧})⟶𝐵 ↔ 𝑔:(𝑤 ∪ {𝑧})⟶𝐵))
19		fvex 6787	. . . . . . . . . 10 ⊢ (𝑓‘𝑥) ∈ V
20		ac6sfi.1	. . . . . . . . . 10 ⊢ (𝑦 = (𝑓‘𝑥) → (𝜑 ↔ 𝜓))
21	19, 20	sbcie 3759	. . . . . . . . 9 ⊢ ([(𝑓‘𝑥) / 𝑦]𝜑 ↔ 𝜓)
22		fveq1 6773	. . . . . . . . . 10 ⊢ (𝑓 = 𝑔 → (𝑓‘𝑥) = (𝑔‘𝑥))
23	22	sbceq1d 3721	. . . . . . . . 9 ⊢ (𝑓 = 𝑔 → ([(𝑓‘𝑥) / 𝑦]𝜑 ↔ [(𝑔‘𝑥) / 𝑦]𝜑))
24	21, 23	bitr3id 285	. . . . . . . 8 ⊢ (𝑓 = 𝑔 → (𝜓 ↔ [(𝑔‘𝑥) / 𝑦]𝜑))
25	24	ralbidv 3112	. . . . . . 7 ⊢ (𝑓 = 𝑔 → (∀𝑥 ∈ (𝑤 ∪ {𝑧})𝜓 ↔ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))
26	18, 25	anbi12d 631	. . . . . 6 ⊢ (𝑓 = 𝑔 → ((𝑓:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})𝜓) ↔ (𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)))
27	26	cbvexvw 2040	. . . . 5 ⊢ (∃𝑓(𝑓:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})𝜓) ↔ ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))
28	17, 27	bitrdi 287	. . . 4 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → (∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)))
29	13, 28	imbi12d 345	. . 3 ⊢ (𝑢 = (𝑤 ∪ {𝑧}) → ((∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓)) ↔ (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))))
30		raleq 3342	. . . 4 ⊢ (𝑢 = 𝐴 → (∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 ↔ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑))
31		feq2 6582	. . . . . 6 ⊢ (𝑢 = 𝐴 → (𝑓:𝑢⟶𝐵 ↔ 𝑓:𝐴⟶𝐵))
32		raleq 3342	. . . . . 6 ⊢ (𝑢 = 𝐴 → (∀𝑥 ∈ 𝑢 𝜓 ↔ ∀𝑥 ∈ 𝐴 𝜓))
33	31, 32	anbi12d 631	. . . . 5 ⊢ (𝑢 = 𝐴 → ((𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ (𝑓:𝐴⟶𝐵 ∧ ∀𝑥 ∈ 𝐴 𝜓)))
34	33	exbidv 1924	. . . 4 ⊢ (𝑢 = 𝐴 → (∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓) ↔ ∃𝑓(𝑓:𝐴⟶𝐵 ∧ ∀𝑥 ∈ 𝐴 𝜓)))
35	30, 34	imbi12d 345	. . 3 ⊢ (𝑢 = 𝐴 → ((∀𝑥 ∈ 𝑢 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑢⟶𝐵 ∧ ∀𝑥 ∈ 𝑢 𝜓)) ↔ (∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝐴⟶𝐵 ∧ ∀𝑥 ∈ 𝐴 𝜓))))
36		f0 6655	. . . 4 ⊢ ∅:∅⟶𝐵
37		0ex 5231	. . . . 5 ⊢ ∅ ∈ V
38		ral0 4443	. . . . . . 7 ⊢ ∀𝑥 ∈ ∅ 𝜓
39	38	biantru 530	. . . . . 6 ⊢ (𝑓:∅⟶𝐵 ↔ (𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓))
40		feq1 6581	. . . . . 6 ⊢ (𝑓 = ∅ → (𝑓:∅⟶𝐵 ↔ ∅:∅⟶𝐵))
41	39, 40	bitr3id 285	. . . . 5 ⊢ (𝑓 = ∅ → ((𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓) ↔ ∅:∅⟶𝐵))
42	37, 41	spcev 3545	. . . 4 ⊢ (∅:∅⟶𝐵 → ∃𝑓(𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓))
43	36, 42	mp1i 13	. . 3 ⊢ (∀𝑥 ∈ ∅ ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:∅⟶𝐵 ∧ ∀𝑥 ∈ ∅ 𝜓))
44		ssun1 4106	. . . . . . 7 ⊢ 𝑤 ⊆ (𝑤 ∪ {𝑧})
45		ssralv 3987	. . . . . . 7 ⊢ (𝑤 ⊆ (𝑤 ∪ {𝑧}) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑))
46	44, 45	ax-mp 5	. . . . . 6 ⊢ (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑)
47	46	imim1i 63	. . . . 5 ⊢ ((∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)))
48		ssun2 4107	. . . . . . . . 9 ⊢ {𝑧} ⊆ (𝑤 ∪ {𝑧})
49		ssralv 3987	. . . . . . . . 9 ⊢ ({𝑧} ⊆ (𝑤 ∪ {𝑧}) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∀𝑥 ∈ {𝑧}∃𝑦 ∈ 𝐵 𝜑))
50	48, 49	ax-mp 5	. . . . . . . 8 ⊢ (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∀𝑥 ∈ {𝑧}∃𝑦 ∈ 𝐵 𝜑)
51		ralsnsg 4604	. . . . . . . . . 10 ⊢ (𝑧 ∈ V → (∀𝑥 ∈ {𝑧}∃𝑦 ∈ 𝐵 𝜑 ↔ [𝑧 / 𝑥]∃𝑦 ∈ 𝐵 𝜑))
52	51	elv 3438	. . . . . . . . 9 ⊢ (∀𝑥 ∈ {𝑧}∃𝑦 ∈ 𝐵 𝜑 ↔ [𝑧 / 𝑥]∃𝑦 ∈ 𝐵 𝜑)
53		sbcrex 3808	. . . . . . . . 9 ⊢ ([𝑧 / 𝑥]∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑦 ∈ 𝐵 [𝑧 / 𝑥]𝜑)
54	52, 53	bitri 274	. . . . . . . 8 ⊢ (∀𝑥 ∈ {𝑧}∃𝑦 ∈ 𝐵 𝜑 ↔ ∃𝑦 ∈ 𝐵 [𝑧 / 𝑥]𝜑)
55	50, 54	sylib 217	. . . . . . 7 ⊢ (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑦 ∈ 𝐵 [𝑧 / 𝑥]𝜑)
56		nfv 1917	. . . . . . . 8 ⊢ Ⅎ𝑦 ¬ 𝑧 ∈ 𝑤
57		nfv 1917	. . . . . . . . 9 ⊢ Ⅎ𝑦∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)
58		nfv 1917	. . . . . . . . . . 11 ⊢ Ⅎ𝑦 𝑔:(𝑤 ∪ {𝑧})⟶𝐵
59		nfcv 2907	. . . . . . . . . . . 12 ⊢ Ⅎ𝑦(𝑤 ∪ {𝑧})
60		nfsbc1v 3736	. . . . . . . . . . . 12 ⊢ Ⅎ𝑦[(𝑔‘𝑥) / 𝑦]𝜑
61	59, 60	nfralw 3151	. . . . . . . . . . 11 ⊢ Ⅎ𝑦∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑
62	58, 61	nfan 1902	. . . . . . . . . 10 ⊢ Ⅎ𝑦(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)
63	62	nfex 2318	. . . . . . . . 9 ⊢ Ⅎ𝑦∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)
64	57, 63	nfim 1899	. . . . . . . 8 ⊢ Ⅎ𝑦(∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))
65		simprl 768	. . . . . . . . . . . . 13 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → 𝑓:𝑤⟶𝐵)
66		vex 3436	. . . . . . . . . . . . . . . 16 ⊢ 𝑧 ∈ V
67		vex 3436	. . . . . . . . . . . . . . . 16 ⊢ 𝑦 ∈ V
68	66, 67	f1osn 6756	. . . . . . . . . . . . . . 15 ⊢ {⟨𝑧, 𝑦⟩}:{𝑧}–1-1-onto→{𝑦}
69		f1of 6716	. . . . . . . . . . . . . . 15 ⊢ ({⟨𝑧, 𝑦⟩}:{𝑧}–1-1-onto→{𝑦} → {⟨𝑧, 𝑦⟩}:{𝑧}⟶{𝑦})
70	68, 69	mp1i 13	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → {⟨𝑧, 𝑦⟩}:{𝑧}⟶{𝑦})
71		simpl2 1191	. . . . . . . . . . . . . . 15 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → 𝑦 ∈ 𝐵)
72	71	snssd 4742	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → {𝑦} ⊆ 𝐵)
73	70, 72	fssd 6618	. . . . . . . . . . . . 13 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → {⟨𝑧, 𝑦⟩}:{𝑧}⟶𝐵)
74		simpl1 1190	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ¬ 𝑧 ∈ 𝑤)
75		disjsn 4647	. . . . . . . . . . . . . 14 ⊢ ((𝑤 ∩ {𝑧}) = ∅ ↔ ¬ 𝑧 ∈ 𝑤)
76	74, 75	sylibr 233	. . . . . . . . . . . . 13 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (𝑤 ∩ {𝑧}) = ∅)
77	65, 73, 76	fun2d 6638	. . . . . . . . . . . 12 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (𝑓 ∪ {⟨𝑧, 𝑦⟩}):(𝑤 ∪ {𝑧})⟶𝐵)
78		simprr 770	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ∀𝑥 ∈ 𝑤 𝜓)
79		eleq1a 2834	. . . . . . . . . . . . . . . . . . 19 ⊢ (𝑥 ∈ 𝑤 → (𝑧 = 𝑥 → 𝑧 ∈ 𝑤))
80	79	necon3bd 2957	. . . . . . . . . . . . . . . . . 18 ⊢ (𝑥 ∈ 𝑤 → (¬ 𝑧 ∈ 𝑤 → 𝑧 ≠ 𝑥))
81	80	impcom 408	. . . . . . . . . . . . . . . . 17 ⊢ ((¬ 𝑧 ∈ 𝑤 ∧ 𝑥 ∈ 𝑤) → 𝑧 ≠ 𝑥)
82		fvunsn 7051	. . . . . . . . . . . . . . . . 17 ⊢ (𝑧 ≠ 𝑥 → ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) = (𝑓‘𝑥))
83		dfsbcq 3718	. . . . . . . . . . . . . . . . . 18 ⊢ (((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) = (𝑓‘𝑥) → ([((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑 ↔ [(𝑓‘𝑥) / 𝑦]𝜑))
84	83, 21	bitr2di 288	. . . . . . . . . . . . . . . . 17 ⊢ (((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) = (𝑓‘𝑥) → (𝜓 ↔ [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
85	81, 82, 84	3syl 18	. . . . . . . . . . . . . . . 16 ⊢ ((¬ 𝑧 ∈ 𝑤 ∧ 𝑥 ∈ 𝑤) → (𝜓 ↔ [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
86	85	ralbidva 3111	. . . . . . . . . . . . . . 15 ⊢ (¬ 𝑧 ∈ 𝑤 → (∀𝑥 ∈ 𝑤 𝜓 ↔ ∀𝑥 ∈ 𝑤 [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
87	74, 86	syl 17	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (∀𝑥 ∈ 𝑤 𝜓 ↔ ∀𝑥 ∈ 𝑤 [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
88	78, 87	mpbid 231	. . . . . . . . . . . . 13 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ∀𝑥 ∈ 𝑤 [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑)
89		simpl3 1192	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → [𝑧 / 𝑥]𝜑)
90		ffun 6603	. . . . . . . . . . . . . . . . 17 ⊢ ((𝑓 ∪ {⟨𝑧, 𝑦⟩}):(𝑤 ∪ {𝑧})⟶𝐵 → Fun (𝑓 ∪ {⟨𝑧, 𝑦⟩}))
91		ssun2 4107	. . . . . . . . . . . . . . . . . 18 ⊢ {⟨𝑧, 𝑦⟩} ⊆ (𝑓 ∪ {⟨𝑧, 𝑦⟩})
92		vsnid 4598	. . . . . . . . . . . . . . . . . . 19 ⊢ 𝑧 ∈ {𝑧}
93	67	dmsnop 6119	. . . . . . . . . . . . . . . . . . 19 ⊢ dom {⟨𝑧, 𝑦⟩} = {𝑧}
94	92, 93	eleqtrri 2838	. . . . . . . . . . . . . . . . . 18 ⊢ 𝑧 ∈ dom {⟨𝑧, 𝑦⟩}
95		funssfv 6795	. . . . . . . . . . . . . . . . . 18 ⊢ ((Fun (𝑓 ∪ {⟨𝑧, 𝑦⟩}) ∧ {⟨𝑧, 𝑦⟩} ⊆ (𝑓 ∪ {⟨𝑧, 𝑦⟩}) ∧ 𝑧 ∈ dom {⟨𝑧, 𝑦⟩}) → ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) = ({⟨𝑧, 𝑦⟩}‘𝑧))
96	91, 94, 95	mp3an23 1452	. . . . . . . . . . . . . . . . 17 ⊢ (Fun (𝑓 ∪ {⟨𝑧, 𝑦⟩}) → ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) = ({⟨𝑧, 𝑦⟩}‘𝑧))
97	77, 90, 96	3syl 18	. . . . . . . . . . . . . . . 16 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) = ({⟨𝑧, 𝑦⟩}‘𝑧))
98	66, 67	fvsn 7053	. . . . . . . . . . . . . . . 16 ⊢ ({⟨𝑧, 𝑦⟩}‘𝑧) = 𝑦
99	97, 98	eqtr2di 2795	. . . . . . . . . . . . . . 15 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → 𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧))
100		ralsnsg 4604	. . . . . . . . . . . . . . . . 17 ⊢ (𝑧 ∈ V → (∀𝑥 ∈ {𝑧}𝜑 ↔ [𝑧 / 𝑥]𝜑))
101	100	elv 3438	. . . . . . . . . . . . . . . 16 ⊢ (∀𝑥 ∈ {𝑧}𝜑 ↔ [𝑧 / 𝑥]𝜑)
102		elsni 4578	. . . . . . . . . . . . . . . . . . . . 21 ⊢ (𝑥 ∈ {𝑧} → 𝑥 = 𝑧)
103	102	fveq2d 6778	. . . . . . . . . . . . . . . . . . . 20 ⊢ (𝑥 ∈ {𝑧} → ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧))
104	103	eqeq2d 2749	. . . . . . . . . . . . . . . . . . 19 ⊢ (𝑥 ∈ {𝑧} → (𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) ↔ 𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧)))
105	104	biimparc 480	. . . . . . . . . . . . . . . . . 18 ⊢ ((𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) ∧ 𝑥 ∈ {𝑧}) → 𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥))
106		sbceq1a 3727	. . . . . . . . . . . . . . . . . 18 ⊢ (𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) → (𝜑 ↔ [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
107	105, 106	syl 17	. . . . . . . . . . . . . . . . 17 ⊢ ((𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) ∧ 𝑥 ∈ {𝑧}) → (𝜑 ↔ [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
108	107	ralbidva 3111	. . . . . . . . . . . . . . . 16 ⊢ (𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) → (∀𝑥 ∈ {𝑧}𝜑 ↔ ∀𝑥 ∈ {𝑧}[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
109	101, 108	bitr3id 285	. . . . . . . . . . . . . . 15 ⊢ (𝑦 = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑧) → ([𝑧 / 𝑥]𝜑 ↔ ∀𝑥 ∈ {𝑧}[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
110	99, 109	syl 17	. . . . . . . . . . . . . 14 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ([𝑧 / 𝑥]𝜑 ↔ ∀𝑥 ∈ {𝑧}[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
111	89, 110	mpbid 231	. . . . . . . . . . . . 13 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ∀𝑥 ∈ {𝑧}[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑)
112		ralun 4126	. . . . . . . . . . . . 13 ⊢ ((∀𝑥 ∈ 𝑤 [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑 ∧ ∀𝑥 ∈ {𝑧}[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑) → ∀𝑥 ∈ (𝑤 ∪ {𝑧})[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑)
113	88, 111, 112	syl2anc 584	. . . . . . . . . . . 12 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ∀𝑥 ∈ (𝑤 ∪ {𝑧})[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑)
114		vex 3436	. . . . . . . . . . . . . 14 ⊢ 𝑓 ∈ V
115		snex 5354	. . . . . . . . . . . . . 14 ⊢ {⟨𝑧, 𝑦⟩} ∈ V
116	114, 115	unex 7596	. . . . . . . . . . . . 13 ⊢ (𝑓 ∪ {⟨𝑧, 𝑦⟩}) ∈ V
117		feq1 6581	. . . . . . . . . . . . . 14 ⊢ (𝑔 = (𝑓 ∪ {⟨𝑧, 𝑦⟩}) → (𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ↔ (𝑓 ∪ {⟨𝑧, 𝑦⟩}):(𝑤 ∪ {𝑧})⟶𝐵))
118		fveq1 6773	. . . . . . . . . . . . . . . 16 ⊢ (𝑔 = (𝑓 ∪ {⟨𝑧, 𝑦⟩}) → (𝑔‘𝑥) = ((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥))
119	118	sbceq1d 3721	. . . . . . . . . . . . . . 15 ⊢ (𝑔 = (𝑓 ∪ {⟨𝑧, 𝑦⟩}) → ([(𝑔‘𝑥) / 𝑦]𝜑 ↔ [((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
120	119	ralbidv 3112	. . . . . . . . . . . . . 14 ⊢ (𝑔 = (𝑓 ∪ {⟨𝑧, 𝑦⟩}) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑 ↔ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑))
121	117, 120	anbi12d 631	. . . . . . . . . . . . 13 ⊢ (𝑔 = (𝑓 ∪ {⟨𝑧, 𝑦⟩}) → ((𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑) ↔ ((𝑓 ∪ {⟨𝑧, 𝑦⟩}):(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑)))
122	116, 121	spcev 3545	. . . . . . . . . . . 12 ⊢ (((𝑓 ∪ {⟨𝑧, 𝑦⟩}):(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[((𝑓 ∪ {⟨𝑧, 𝑦⟩})‘𝑥) / 𝑦]𝜑) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))
123	77, 113, 122	syl2anc 584	. . . . . . . . . . 11 ⊢ (((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) ∧ (𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))
124	123	ex 413	. . . . . . . . . 10 ⊢ ((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) → ((𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)))
125	124	exlimdv 1936	. . . . . . . . 9 ⊢ ((¬ 𝑧 ∈ 𝑤 ∧ 𝑦 ∈ 𝐵 ∧ [𝑧 / 𝑥]𝜑) → (∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)))
126	125	3exp 1118	. . . . . . . 8 ⊢ (¬ 𝑧 ∈ 𝑤 → (𝑦 ∈ 𝐵 → ([𝑧 / 𝑥]𝜑 → (∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑)))))
127	56, 64, 126	rexlimd 3250	. . . . . . 7 ⊢ (¬ 𝑧 ∈ 𝑤 → (∃𝑦 ∈ 𝐵 [𝑧 / 𝑥]𝜑 → (∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))))
128	55, 127	syl5 34	. . . . . 6 ⊢ (¬ 𝑧 ∈ 𝑤 → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → (∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓) → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))))
129	128	a2d 29	. . . . 5 ⊢ (¬ 𝑧 ∈ 𝑤 → ((∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))))
130	47, 129	syl5 34	. . . 4 ⊢ (¬ 𝑧 ∈ 𝑤 → ((∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))))
131	130	adantl 482	. . 3 ⊢ ((𝑤 ∈ Fin ∧ ¬ 𝑧 ∈ 𝑤) → ((∀𝑥 ∈ 𝑤 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝑤⟶𝐵 ∧ ∀𝑥 ∈ 𝑤 𝜓)) → (∀𝑥 ∈ (𝑤 ∪ {𝑧})∃𝑦 ∈ 𝐵 𝜑 → ∃𝑔(𝑔:(𝑤 ∪ {𝑧})⟶𝐵 ∧ ∀𝑥 ∈ (𝑤 ∪ {𝑧})[(𝑔‘𝑥) / 𝑦]𝜑))))
132	6, 12, 29, 35, 43, 131	findcard2s 8948	. 2 ⊢ (𝐴 ∈ Fin → (∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑 → ∃𝑓(𝑓:𝐴⟶𝐵 ∧ ∀𝑥 ∈ 𝐴 𝜓)))
133	132	imp 407	1 ⊢ ((𝐴 ∈ Fin ∧ ∀𝑥 ∈ 𝐴 ∃𝑦 ∈ 𝐵 𝜑) → ∃𝑓(𝑓:𝐴⟶𝐵 ∧ ∀𝑥 ∈ 𝐴 𝜓))

Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 205   ∧ wa 396   ∧ w3a 1086   = wceq 1539  ∃wex 1782   ∈ wcel 2106   ≠ wne 2943  ∀wral 3064  ∃wrex 3065  Vcvv 3432  [wsbc 3716   ∪ cun 3885   ∩ cin 3886   ⊆ wss 3887  ∅c0 4256  {csn 4561  ⟨cop 4567  dom cdm 5589  Fun wfun 6427  ⟶wf 6429  –1-1-onto→wf1o 6432  ‘cfv 6433  Fincfn 8733

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1913  ax-6 1971  ax-7 2011  ax-8 2108  ax-9 2116  ax-10 2137  ax-11 2154  ax-12 2171  ax-ext 2709  ax-sep 5223  ax-nul 5230  ax-pr 5352  ax-un 7588

This theorem depends on definitions:  df-bi 206  df-an 397  df-or 845  df-3or 1087  df-3an 1088  df-tru 1542  df-fal 1552  df-ex 1783  df-nf 1787  df-sb 2068  df-mo 2540  df-eu 2569  df-clab 2716  df-cleq 2730  df-clel 2816  df-nfc 2889  df-ne 2944  df-ral 3069  df-rex 3070  df-reu 3072  df-rab 3073  df-v 3434  df-sbc 3717  df-dif 3890  df-un 3892  df-in 3894  df-ss 3904  df-pss 3906  df-nul 4257  df-if 4460  df-pw 4535  df-sn 4562  df-pr 4564  df-op 4568  df-uni 4840  df-br 5075  df-opab 5137  df-tr 5192  df-id 5489  df-eprel 5495  df-po 5503  df-so 5504  df-fr 5544  df-we 5546  df-xp 5595  df-rel 5596  df-cnv 5597  df-co 5598  df-dm 5599  df-rn 5600  df-res 5601  df-ima 5602  df-ord 6269  df-on 6270  df-lim 6271  df-suc 6272  df-iota 6391  df-fun 6435  df-fn 6436  df-f 6437  df-f1 6438  df-fo 6439  df-f1o 6440  df-fv 6441  df-om 7713  df-en 8734  df-fin 8737

This theorem is referenced by:  fissuni  9124  fipreima  9125  indexfi  9127  finacn  9806  axcc4dom  10197  ttukeylem6  10270  firest  17143  ablfaclem3  19690  ablfac2  19692  cmpcovf  22542  cmpsub  22551  tgcmp  22552  hauscmplem  22557  comppfsc  22683  ptcnplem  22772  alexsubALTlem3  23200  alexsubALT  23202  tsmsxplem1  23304  ovolicc2lem5  24685  ovolicc2  24686  limciun  25058  cvmliftlem15  33260  matunitlindflem2  35774  ptrecube  35777  istotbnd3  35929  sstotbnd2  35932  sstotbnd  35933  prdsbnd  35951  prdstotbnd  35952  heiborlem1  35969  heibor  35979  kelac1  40888  hbt  40955