Theorem rspcebdv 3584

Description: Restricted existential specialization, using implicit substitution in both directions. (Contributed by AV, 8-Jan-2022.)

Hypotheses

Ref	Expression
rspcdv.1	⊢ (𝜑 → 𝐴 ∈ 𝐵)
rspcdv.2	⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒))
rspcebdv.1	⊢ ((𝜑 ∧ 𝜓) → 𝑥 = 𝐴)

Assertion

Ref	Expression
rspcebdv	⊢ (𝜑 → (∃𝑥 ∈ 𝐵 𝜓 ↔ 𝜒))

Distinct variable groups:   𝑥,𝐴   𝑥,𝐵   𝜑,𝑥   𝜒,𝑥

Allowed substitution hint:   𝜓(𝑥)

Proof of Theorem rspcebdv

Step	Hyp	Ref	Expression
1		rspcebdv.1	. . . . . . 7 ⊢ ((𝜑 ∧ 𝜓) → 𝑥 = 𝐴)
2		rspcdv.2	. . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒))
3	1, 2	syldan 602	. . . . . 6 ⊢ ((𝜑 ∧ 𝜓) → (𝜓 ↔ 𝜒))
4	3	biimpd 232	. . . . 5 ⊢ ((𝜑 ∧ 𝜓) → (𝜓 → 𝜒))
5	4	expcom 418	. . . 4 ⊢ (𝜓 → (𝜑 → (𝜓 → 𝜒)))
6	5	pm2.43b 56	. . 3 ⊢ (𝜑 → (𝜓 → 𝜒))
7	6	rexlimdvw 3177	. 2 ⊢ (𝜑 → (∃𝑥 ∈ 𝐵 𝜓 → 𝜒))
8		rspcdv.1	. . 3 ⊢ (𝜑 → 𝐴 ∈ 𝐵)
9	8, 2	rspcedv 3583	. 2 ⊢ (𝜑 → (𝜒 → ∃𝑥 ∈ 𝐵 𝜓))
10	7, 9	impbid 215	1 ⊢ (𝜑 → (∃𝑥 ∈ 𝐵 𝜓 ↔ 𝜒))

Syntax hints:   → wi 4   ↔ wb 209   ∧ wa 400   = wceq 1567   ∈ wcel 2149  ∃wrex 3095

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-ext 2741

This theorem depends on definitions:  df-bi 210  df-an 401  df-tru 1570  df-ex 1807  df-sb 2098  df-clab 2748  df-cleq 2761  df-clel 2844  df-ral 3086  df-rex 3096

This theorem is referenced by:  fusgr2wsp2nb  30625