Theorem reuxfr2d 4891

Description: Transfer existential uniqueness from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. (Contributed by NM, 16-Jan-2012.) (Revised by NM, 16-Jun-2017.)

Hypotheses

Ref	Expression
reuxfr2d.1	⊢ ((𝜑 ∧ 𝑦 ∈ 𝐵) → 𝐴 ∈ 𝐵)
reuxfr2d.2	⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃*𝑦 ∈ 𝐵 𝑥 = 𝐴)

Assertion

Ref	Expression
reuxfr2d	⊢ (𝜑 → (∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∃!𝑦 ∈ 𝐵 𝜓))

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

Allowed substitution hints:   𝜓(𝑦)   𝐴(𝑦)

Proof of Theorem reuxfr2d

Step	Hyp	Ref	Expression
1		reuxfr2d.2	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃*𝑦 ∈ 𝐵 𝑥 = 𝐴)
2		rmoan 3406	. . . . . . 7 ⊢ (∃*𝑦 ∈ 𝐵 𝑥 = 𝐴 → ∃*𝑦 ∈ 𝐵 (𝜓 ∧ 𝑥 = 𝐴))
3	1, 2	syl 17	. . . . . 6 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃*𝑦 ∈ 𝐵 (𝜓 ∧ 𝑥 = 𝐴))
4		ancom 466	. . . . . . 7 ⊢ ((𝜓 ∧ 𝑥 = 𝐴) ↔ (𝑥 = 𝐴 ∧ 𝜓))
5	4	rmobii 3133	. . . . . 6 ⊢ (∃*𝑦 ∈ 𝐵 (𝜓 ∧ 𝑥 = 𝐴) ↔ ∃*𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓))
6	3, 5	sylib 208	. . . . 5 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃*𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓))
7	6	ralrimiva 2966	. . . 4 ⊢ (𝜑 → ∀𝑥 ∈ 𝐵 ∃*𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓))
8		2reuswap 3410	. . . 4 ⊢ (∀𝑥 ∈ 𝐵 ∃*𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → (∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → ∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓)))
9	7, 8	syl 17	. . 3 ⊢ (𝜑 → (∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → ∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓)))
10		df-rmo 2920	. . . . . 6 ⊢ (∃*𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∃*𝑥(𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)))
11	10	ralbii 2980	. . . . 5 ⊢ (∀𝑦 ∈ 𝐵 ∃*𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∀𝑦 ∈ 𝐵 ∃*𝑥(𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)))
12		2reuswap 3410	. . . . 5 ⊢ (∀𝑦 ∈ 𝐵 ∃*𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → (∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → ∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓)))
13	11, 12	sylbir 225	. . . 4 ⊢ (∀𝑦 ∈ 𝐵 ∃*𝑥(𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)) → (∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → ∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓)))
14		moeq 3382	. . . . . . 7 ⊢ ∃*𝑥 𝑥 = 𝐴
15	14	moani 2525	. . . . . 6 ⊢ ∃*𝑥((𝑥 ∈ 𝐵 ∧ 𝜓) ∧ 𝑥 = 𝐴)
16		ancom 466	. . . . . . . 8 ⊢ (((𝑥 ∈ 𝐵 ∧ 𝜓) ∧ 𝑥 = 𝐴) ↔ (𝑥 = 𝐴 ∧ (𝑥 ∈ 𝐵 ∧ 𝜓)))
17		an12 838	. . . . . . . 8 ⊢ ((𝑥 = 𝐴 ∧ (𝑥 ∈ 𝐵 ∧ 𝜓)) ↔ (𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)))
18	16, 17	bitri 264	. . . . . . 7 ⊢ (((𝑥 ∈ 𝐵 ∧ 𝜓) ∧ 𝑥 = 𝐴) ↔ (𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)))
19	18	mobii 2493	. . . . . 6 ⊢ (∃*𝑥((𝑥 ∈ 𝐵 ∧ 𝜓) ∧ 𝑥 = 𝐴) ↔ ∃*𝑥(𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)))
20	15, 19	mpbi 220	. . . . 5 ⊢ ∃*𝑥(𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓))
21	20	a1i 11	. . . 4 ⊢ (𝑦 ∈ 𝐵 → ∃*𝑥(𝑥 ∈ 𝐵 ∧ (𝑥 = 𝐴 ∧ 𝜓)))
22	13, 21	mprg 2926	. . 3 ⊢ (∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) → ∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓))
23	9, 22	impbid1 215	. 2 ⊢ (𝜑 → (∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓)))
24		reuxfr2d.1	. . . 4 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐵) → 𝐴 ∈ 𝐵)
25		biidd 252	. . . . 5 ⊢ (𝑥 = 𝐴 → (𝜓 ↔ 𝜓))
26	25	ceqsrexv 3336	. . . 4 ⊢ (𝐴 ∈ 𝐵 → (∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ 𝜓))
27	24, 26	syl 17	. . 3 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐵) → (∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ 𝜓))
28	27	reubidva 3125	. 2 ⊢ (𝜑 → (∃!𝑦 ∈ 𝐵 ∃𝑥 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∃!𝑦 ∈ 𝐵 𝜓))
29	23, 28	bitrd 268	1 ⊢ (𝜑 → (∃!𝑥 ∈ 𝐵 ∃𝑦 ∈ 𝐵 (𝑥 = 𝐴 ∧ 𝜓) ↔ ∃!𝑦 ∈ 𝐵 𝜓))

Syntax hints:   → wi 4   ↔ wb 196   ∧ wa 384   = wceq 1483   ∈ wcel 1990  ∃*wmo 2471  ∀wral 2912  ∃wrex 2913  ∃!wreu 2914  ∃*wrmo 2915

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-ral 2917  df-rex 2918  df-reu 2919  df-rmo 2920  df-v 3202

This theorem is referenced by:  reuxfr2  4892  reuxfrd  4893