Theorem cbvreud 38390

Description: Deduction used to change bound variables in a restricted existential uniqueness quantifier. (Contributed by ML, 27-Mar-2021.)

Hypotheses

Ref	Expression
cbvreud.1	⊢ Ⅎ𝑥𝜑
cbvreud.2	⊢ Ⅎ𝑦𝜑
cbvreud.3	⊢ (𝜑 → Ⅎ𝑦𝜓)
cbvreud.4	⊢ (𝜑 → Ⅎ𝑥𝜒)
cbvreud.5	⊢ (𝜑 → (𝑥 = 𝑦 → (𝜓 ↔ 𝜒)))

Assertion

Ref	Expression
cbvreud	⊢ (𝜑 → (∃!𝑥 ∈ 𝐴 𝜓 ↔ ∃!𝑦 ∈ 𝐴 𝜒))

Distinct variable group:   𝑥,𝐴,𝑦

Allowed substitution hints:   𝜑(𝑥, 𝑦)   𝜓(𝑥, 𝑦)   𝜒(𝑥, 𝑦)

Proof of Theorem cbvreud

Step	Hyp	Ref	Expression
1		cbvreud.1	. . 3 ⊢ Ⅎ𝑥𝜑
2		cbvreud.2	. . 3 ⊢ Ⅎ𝑦𝜑
3		nfvd 1947	. . . 4 ⊢ (𝜑 → Ⅎ𝑦 𝑥 ∈ 𝐴)
4		cbvreud.3	. . . 4 ⊢ (𝜑 → Ⅎ𝑦𝜓)
5	3, 4	nfand 1929	. . 3 ⊢ (𝜑 → Ⅎ𝑦(𝑥 ∈ 𝐴 ∧ 𝜓))
6		nfvd 1947	. . . 4 ⊢ (𝜑 → Ⅎ𝑥 𝑦 ∈ 𝐴)
7		cbvreud.4	. . . 4 ⊢ (𝜑 → Ⅎ𝑥𝜒)
8	6, 7	nfand 1929	. . 3 ⊢ (𝜑 → Ⅎ𝑥(𝑦 ∈ 𝐴 ∧ 𝜒))
9		eleq1 2848	. . . . . 6 ⊢ (𝑥 = 𝑦 → (𝑥 ∈ 𝐴 ↔ 𝑦 ∈ 𝐴))
10	9	adantl 487	. . . . 5 ⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝑥 ∈ 𝐴 ↔ 𝑦 ∈ 𝐴))
11		cbvreud.5	. . . . . 6 ⊢ (𝜑 → (𝑥 = 𝑦 → (𝜓 ↔ 𝜒)))
12	11	imp 412	. . . . 5 ⊢ ((𝜑 ∧ 𝑥 = 𝑦) → (𝜓 ↔ 𝜒))
13	10, 12	anbi12d 644	. . . 4 ⊢ ((𝜑 ∧ 𝑥 = 𝑦) → ((𝑥 ∈ 𝐴 ∧ 𝜓) ↔ (𝑦 ∈ 𝐴 ∧ 𝜒)))
14	13	ex 418	. . 3 ⊢ (𝜑 → (𝑥 = 𝑦 → ((𝑥 ∈ 𝐴 ∧ 𝜓) ↔ (𝑦 ∈ 𝐴 ∧ 𝜒))))
15	1, 2, 5, 8, 14	cbveud 38389	. 2 ⊢ (𝜑 → (∃!𝑥(𝑥 ∈ 𝐴 ∧ 𝜓) ↔ ∃!𝑦(𝑦 ∈ 𝐴 ∧ 𝜒)))
16		df-reu 3366	. 2 ⊢ (∃!𝑥 ∈ 𝐴 𝜓 ↔ ∃!𝑥(𝑥 ∈ 𝐴 ∧ 𝜓))
17		df-reu 3366	. 2 ⊢ (∃!𝑦 ∈ 𝐴 𝜒 ↔ ∃!𝑦(𝑦 ∈ 𝐴 ∧ 𝜒))
18	15, 16, 17	3bitr4g 317	1 ⊢ (𝜑 → (∃!𝑥 ∈ 𝐴 𝜓 ↔ ∃!𝑦 ∈ 𝐴 𝜒))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   = wceq 1569  Ⅎwnf 1815   ∈ wcel 2144  ∃!weu 2593  ∃!wreu 3363

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-ex 1812  df-nf 1816  df-mo 2564  df-eu 2594  df-cleq 2752  df-clel 2835  df-reu 3366

This theorem is used by:  fvineqsneu  38428