Theorem nfccdeq 3691

Description: Variation of nfcdeq 3690 for classes. Usage of this theorem is discouraged because it depends on ax-13 2371. (Contributed by Mario Carneiro, 11-Aug-2016.) Avoid ax-11 2158. (Revised by Gino Giotto, 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 2891	. . 3 ⊢ Ⅎ𝑥 𝑧 ∈ 𝐴
3		eqid 2737	. . . . 5 ⊢ 𝑧 = 𝑧
4	3	cdeqth 3680	. . . 4 ⊢ CondEq(𝑥 = 𝑦 → 𝑧 = 𝑧)
5		nfccdeq.2	. . . 4 ⊢ CondEq(𝑥 = 𝑦 → 𝐴 = 𝐵)
6	4, 5	cdeqel 3689	. . 3 ⊢ CondEq(𝑥 = 𝑦 → (𝑧 ∈ 𝐴 ↔ 𝑧 ∈ 𝐵))
7	2, 6	nfcdeq 3690	. 2 ⊢ (𝑧 ∈ 𝐴 ↔ 𝑧 ∈ 𝐵)
8	7	eqriv 2734	1 ⊢ 𝐴 = 𝐵

Syntax hints:   = wceq 1543   ∈ wcel 2110  Ⅎwnfc 2884  CondEqwcdeq 3676

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1803  ax-4 1817  ax-5 1918  ax-6 1976  ax-7 2016  ax-8 2112  ax-9 2120  ax-10 2141  ax-12 2175  ax-13 2371  ax-ext 2708

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 848  df-ex 1788  df-nf 1792  df-sb 2071  df-cleq 2729  df-clel 2816  df-nfc 2886  df-cdeq 3677

This theorem is referenced by: (None)