Theorem bj-ceqsalg 34205

Description: Remove from ceqsalg 3529 dependency on ax-ext 2793 (and on df-cleq 2814 and df-v 3496). See also bj-ceqsalgv 34207. (Contributed by BJ, 12-Oct-2019.) (Proof modification is discouraged.)

Hypotheses

Ref	Expression
bj-ceqsalg.1	⊢ Ⅎ𝑥𝜓
bj-ceqsalg.2	⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))

Assertion

Ref	Expression
bj-ceqsalg	⊢ (𝐴 ∈ 𝑉 → (∀𝑥(𝑥 = 𝐴 → 𝜑) ↔ 𝜓))

Distinct variable group:   𝑥,𝐴

Allowed substitution hints:   𝜑(𝑥)   𝜓(𝑥)   𝑉(𝑥)

Proof of Theorem bj-ceqsalg

Step	Hyp	Ref	Expression
1		bj-elisset 34192	. 2 ⊢ (𝐴 ∈ 𝑉 → ∃𝑥 𝑥 = 𝐴)
2		bj-ceqsalg.1	. . 3 ⊢ Ⅎ𝑥𝜓
3		bj-ceqsalg.2	. . 3 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜓))
4	2, 3	bj-ceqsalg0 34204	. 2 ⊢ (∃𝑥 𝑥 = 𝐴 → (∀𝑥(𝑥 = 𝐴 → 𝜑) ↔ 𝜓))
5	1, 4	syl 17	1 ⊢ (𝐴 ∈ 𝑉 → (∀𝑥(𝑥 = 𝐴 → 𝜑) ↔ 𝜓))

Syntax hints:   → wi 4   ↔ wb 208  ∀wal 1531   = wceq 1533  ∃wex 1776  Ⅎwnf 1780   ∈ wcel 2110

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1907  ax-6 1966  ax-7 2011  ax-8 2112  ax-12 2173

This theorem depends on definitions:  df-bi 209  df-an 399  df-3an 1085  df-ex 1777  df-nf 1781  df-sb 2066  df-clab 2800  df-clel 2893

This theorem is referenced by: (None)