Theorem nfccdeq 3740

Description: Variation of nfcdeq 3739 for classes. Usage of this theorem is discouraged because it depends on ax-13 2403. (Contributed by Mario Carneiro, 11-Aug-2016.) Avoid ax-11 2191. (Revised by GG, 19-May-2023.) (New usage is discouraged.)

Hypotheses

Ref	Expression
nfccdeq.1	⊢ Ⅎ𝑥𝐴
nfccdeq.2	⊢ CondEq(𝑥 = 𝑦 → 𝐴 = 𝐵)

Assertion

Ref	Expression
nfccdeq	⊢ 𝐴 = 𝐵

Distinct variable group:   𝑥,𝐵

Allowed substitution hints:   𝐴(𝑥, 𝑦)   𝐵(𝑦)

Proof of Theorem nfccdeq

Dummy variable 𝑧 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		nfccdeq.1	. . . 4 ⊢ Ⅎ𝑥𝐴
2	1	nfcri 2916	. . 3 ⊢ Ⅎ𝑥 𝑧 ∈ 𝐴
3		eqid 2762	. . . . 5 ⊢ 𝑧 = 𝑧
4	3	cdeqth 3729	. . . 4 ⊢ CondEq(𝑥 = 𝑦 → 𝑧 = 𝑧)
5		nfccdeq.2	. . . 4 ⊢ CondEq(𝑥 = 𝑦 → 𝐴 = 𝐵)
6	4, 5	cdeqel 3738	. . 3 ⊢ CondEq(𝑥 = 𝑦 → (𝑧 ∈ 𝐴 ↔ 𝑧 ∈ 𝐵))
7	2, 6	nfcdeq 3739	. 2 ⊢ (𝑧 ∈ 𝐴 ↔ 𝑧 ∈ 𝐵)
8	7	eqriv 2759	1 ⊢ 𝐴 = 𝐵

This proof depends on syntax axioms:   = wceq 1569   ∈ wcel 2142  Ⅎwnfc 2909  CondEqwcdeq 3725

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1824  ax-4 1838  ax-5 1939  ax-6 1996  ax-7 2037  ax-8 2144  ax-9 2152  ax-10 2175  ax-12 2212  ax-13 2403  ax-ext 2734

This proof depends on definitions:  df-bi 210  df-an 401  df-or 861  df-ex 1809  df-nf 1813  df-sb 2096  df-cleq 2754  df-clel 2837  df-nfc 2911  df-cdeq 3726

This theorem is used by: (None)