Theorem riota5f 7405

Description: A method for computing restricted iota. (Contributed by NM, 16-Apr-2013.) (Revised by Mario Carneiro, 15-Oct-2016.)

Hypotheses

Ref	Expression
riota5f.1	⊢ (𝜑 → Ⅎ𝑥𝐵)
riota5f.2	⊢ (𝜑 → 𝐵 ∈ 𝐴)
riota5f.3	⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝜓 ↔ 𝑥 = 𝐵))

Assertion

Ref	Expression
riota5f	⊢ (𝜑 → (℩𝑥 ∈ 𝐴 𝜓) = 𝐵)

Distinct variable groups:   𝑥,𝐴   𝜑,𝑥

Allowed substitution hints:   𝜓(𝑥)   𝐵(𝑥)

Proof of Theorem riota5f

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		riota5f.3	. . 3 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝜓 ↔ 𝑥 = 𝐵))
2	1	ralrimiva 3154	. 2 ⊢ (𝜑 → ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝐵))
3		riota5f.2	. . . 4 ⊢ (𝜑 → 𝐵 ∈ 𝐴)
4		trud 1579	. . . . . . 7 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → ⊤)
5		reu6i 3685	. . . . . . . . 9 ⊢ ((𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦)) → ∃!𝑥 ∈ 𝐴 𝜓)
6	5	adantl 487	. . . . . . . 8 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → ∃!𝑥 ∈ 𝐴 𝜓)
7		nfv 1946	. . . . . . . . . 10 ⊢ Ⅎ𝑥𝜑
8		nfv 1946	. . . . . . . . . . 11 ⊢ Ⅎ𝑥 𝑦 ∈ 𝐴
9		nfra1 3286	. . . . . . . . . . 11 ⊢ Ⅎ𝑥∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦)
10	8, 9	nfan 1931	. . . . . . . . . 10 ⊢ Ⅎ𝑥(𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))
11	7, 10	nfan 1931	. . . . . . . . 9 ⊢ Ⅎ𝑥(𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦)))
12		nfcvd 2923	. . . . . . . . 9 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → Ⅎ𝑥𝑦)
13		nfvd 1947	. . . . . . . . 9 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → Ⅎ𝑥⊤)
14		simprl 783	. . . . . . . . 9 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → 𝑦 ∈ 𝐴)
15		simpr 490	. . . . . . . . . . 11 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → 𝑥 = 𝑦)
16		simplrr 790	. . . . . . . . . . . 12 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))
17		simplrl 789	. . . . . . . . . . . . 13 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → 𝑦 ∈ 𝐴)
18	15, 17	eqeltrd 2860	. . . . . . . . . . . 12 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → 𝑥 ∈ 𝐴)
19		rsp 3250	. . . . . . . . . . . 12 ⊢ (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (𝑥 ∈ 𝐴 → (𝜓 ↔ 𝑥 = 𝑦)))
20	16, 18, 19	sylc 66	. . . . . . . . . . 11 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝑥 = 𝑦))
21	15, 20	mpbird 260	. . . . . . . . . 10 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → 𝜓)
22		trud 1579	. . . . . . . . . 10 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → ⊤)
23	21, 22	2thd 268	. . . . . . . . 9 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ 𝑥 = 𝑦) → (𝜓 ↔ ⊤))
24	11, 12, 13, 14, 23	riota2df 7400	. . . . . . . 8 ⊢ (((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) ∧ ∃!𝑥 ∈ 𝐴 𝜓) → (⊤ ↔ (℩𝑥 ∈ 𝐴 𝜓) = 𝑦))
25	6, 24	mpdan 700	. . . . . . 7 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → (⊤ ↔ (℩𝑥 ∈ 𝐴 𝜓) = 𝑦))
26	4, 25	mpbid 235	. . . . . 6 ⊢ ((𝜑 ∧ (𝑦 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦))) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦)
27	26	expr 462	. . . . 5 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐴) → (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦))
28	27	ralrimiva 3154	. . . 4 ⊢ (𝜑 → ∀𝑦 ∈ 𝐴 (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦))
29		rspsbc 3825	. . . 4 ⊢ (𝐵 ∈ 𝐴 → (∀𝑦 ∈ 𝐴 (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦) → [𝐵 / 𝑦](∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦)))
30	3, 28, 29	sylc 66	. . 3 ⊢ (𝜑 → [𝐵 / 𝑦](∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦))
31		nfcvd 2923	. . . . . . . 8 ⊢ (𝜑 → Ⅎ𝑥𝑦)
32		riota5f.1	. . . . . . . 8 ⊢ (𝜑 → Ⅎ𝑥𝐵)
33	31, 32	nfeqd 2932	. . . . . . 7 ⊢ (𝜑 → Ⅎ𝑥 𝑦 = 𝐵)
34	7, 33	nfan1 2236	. . . . . 6 ⊢ Ⅎ𝑥(𝜑 ∧ 𝑦 = 𝐵)
35		simpr 490	. . . . . . . 8 ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → 𝑦 = 𝐵)
36	35	eqeq2d 2771	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → (𝑥 = 𝑦 ↔ 𝑥 = 𝐵))
37	36	bibi2d 345	. . . . . 6 ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → ((𝜓 ↔ 𝑥 = 𝑦) ↔ (𝜓 ↔ 𝑥 = 𝐵)))
38	34, 37	ralbid 3275	. . . . 5 ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) ↔ ∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝐵)))
39	35	eqeq2d 2771	. . . . 5 ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → ((℩𝑥 ∈ 𝐴 𝜓) = 𝑦 ↔ (℩𝑥 ∈ 𝐴 𝜓) = 𝐵))
40	38, 39	imbi12d 347	. . . 4 ⊢ ((𝜑 ∧ 𝑦 = 𝐵) → ((∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦) ↔ (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝐵) → (℩𝑥 ∈ 𝐴 𝜓) = 𝐵)))
41	3, 40	sbcied 3781	. . 3 ⊢ (𝜑 → ([𝐵 / 𝑦](∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝑦) → (℩𝑥 ∈ 𝐴 𝜓) = 𝑦) ↔ (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝐵) → (℩𝑥 ∈ 𝐴 𝜓) = 𝐵)))
42	30, 41	mpbid 235	. 2 ⊢ (𝜑 → (∀𝑥 ∈ 𝐴 (𝜓 ↔ 𝑥 = 𝐵) → (℩𝑥 ∈ 𝐴 𝜓) = 𝐵))
43	2, 42	mpd 16	1 ⊢ (𝜑 → (℩𝑥 ∈ 𝐴 𝜓) = 𝐵)

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1569  ⊤wtru 1570   ∈ wcel 2144  Ⅎwnfc 2907  ∀wral 3076  ∃!wreu 3363  [wsbc 3738  ℩crio 7376

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1942  ax-6 1999  ax-7 2040  ax-8 2146  ax-9 2154  ax-10 2177  ax-11 2193  ax-12 2212  ax-ext 2732

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1572  df-ex 1812  df-nf 1816  df-sb 2099  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ral 3077  df-rex 3087  df-reu 3366  df-v 3452  df-sbc 3739  df-ss 3896  df-un 4151  df-sn 4584  df-pr 4586  df-uni 4867  df-iota 6494  df-riota 7377

This theorem is used by:  riota5  7406