Theorem ixpeq1i 36156

Description: Equality inference for infinite Cartesian product. (Contributed by GG, 1-Sep-2025.)

Hypothesis

Ref	Expression
ixpeq1i.1	⊢ 𝐴 = 𝐵

Assertion

Ref	Expression
ixpeq1i	⊢ X𝑥 ∈ 𝐴 𝐶 = X𝑥 ∈ 𝐵 𝐶

Proof of Theorem ixpeq1i

Dummy variable 𝑓 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		ixpeq1i.1	. . . . . . 7 ⊢ 𝐴 = 𝐵
2	1	eleq2i 2836	. . . . . 6 ⊢ (𝑥 ∈ 𝐴 ↔ 𝑥 ∈ 𝐵)
3	2	abbii 2812	. . . . 5 ⊢ {𝑥 ∣ 𝑥 ∈ 𝐴} = {𝑥 ∣ 𝑥 ∈ 𝐵}
4	3	fneq2i 6672	. . . 4 ⊢ (𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐴} ↔ 𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐵})
5	2	imbi1i 349	. . . . 5 ⊢ ((𝑥 ∈ 𝐴 → (𝑓‘𝑥) ∈ 𝐶) ↔ (𝑥 ∈ 𝐵 → (𝑓‘𝑥) ∈ 𝐶))
6	5	ralbii2 3095	. . . 4 ⊢ (∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶 ↔ ∀𝑥 ∈ 𝐵 (𝑓‘𝑥) ∈ 𝐶)
7	4, 6	anbi12i 627	. . 3 ⊢ ((𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐴} ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶) ↔ (𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐵} ∧ ∀𝑥 ∈ 𝐵 (𝑓‘𝑥) ∈ 𝐶))
8	7	abbii 2812	. 2 ⊢ {𝑓 ∣ (𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐴} ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶)} = {𝑓 ∣ (𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐵} ∧ ∀𝑥 ∈ 𝐵 (𝑓‘𝑥) ∈ 𝐶)}
9		df-ixp 8950	. 2 ⊢ X𝑥 ∈ 𝐴 𝐶 = {𝑓 ∣ (𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐴} ∧ ∀𝑥 ∈ 𝐴 (𝑓‘𝑥) ∈ 𝐶)}
10		df-ixp 8950	. 2 ⊢ X𝑥 ∈ 𝐵 𝐶 = {𝑓 ∣ (𝑓 Fn {𝑥 ∣ 𝑥 ∈ 𝐵} ∧ ∀𝑥 ∈ 𝐵 (𝑓‘𝑥) ∈ 𝐶)}
11	8, 9, 10	3eqtr4i 2778	1 ⊢ X𝑥 ∈ 𝐴 𝐶 = X𝑥 ∈ 𝐵 𝐶

Syntax hints:   ∧ wa 395   = wceq 1537   ∈ wcel 2108  {cab 2717  ∀wral 3067   Fn wfn 6563  ‘cfv 6568  Xcixp 8949

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1793  ax-4 1807  ax-5 1909  ax-6 1967  ax-7 2007  ax-8 2110  ax-9 2118  ax-ext 2711

This theorem depends on definitions:  df-bi 207  df-an 396  df-ex 1778  df-sb 2065  df-clab 2718  df-cleq 2732  df-clel 2819  df-ral 3068  df-fn 6571  df-ixp 8950

This theorem is referenced by:  ixpeq12i  36157