Theorem iinxp 49449

Description: Indexed intersection of Cartesian products is the Cartesian product of indexed intersections. See also inxp 5804 and intxp 49450. (Contributed by Zhi Wang, 30-Oct-2025.)

Assertion

Ref	Expression
iinxp	⊢ (𝐴 ≠ ∅ → ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) = (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶))

Distinct variable group:   𝑥,𝐴

Allowed substitution hints:   𝐵(𝑥)   𝐶(𝑥)

Proof of Theorem iinxp

Dummy variables 𝑦 𝑧 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		relxp 5665	. . . . 5 ⊢ Rel (𝐵 × 𝐶)
2	1	rgenw 3080	. . . 4 ⊢ ∀𝑥 ∈ 𝐴 Rel (𝐵 × 𝐶)
3		r19.2z 4453	. . . 4 ⊢ ((𝐴 ≠ ∅ ∧ ∀𝑥 ∈ 𝐴 Rel (𝐵 × 𝐶)) → ∃𝑥 ∈ 𝐴 Rel (𝐵 × 𝐶))
4	2, 3	mpan2 701	. . 3 ⊢ (𝐴 ≠ ∅ → ∃𝑥 ∈ 𝐴 Rel (𝐵 × 𝐶))
5		reliin 5790	. . 3 ⊢ (∃𝑥 ∈ 𝐴 Rel (𝐵 × 𝐶) → Rel ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶))
6	4, 5	syl 17	. 2 ⊢ (𝐴 ≠ ∅ → Rel ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶))
7		relxp 5665	. 2 ⊢ Rel (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶)
8		eliin 4954	. . . . . 6 ⊢ (𝑦 ∈ V → (𝑦 ∈ ∩ 𝑥 ∈ 𝐴 𝐵 ↔ ∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵))
9	8	elv 3459	. . . . 5 ⊢ (𝑦 ∈ ∩ 𝑥 ∈ 𝐴 𝐵 ↔ ∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵)
10		eliin 4954	. . . . . 6 ⊢ (𝑧 ∈ V → (𝑧 ∈ ∩ 𝑥 ∈ 𝐴 𝐶 ↔ ∀𝑥 ∈ 𝐴 𝑧 ∈ 𝐶))
11	10	elv 3459	. . . . 5 ⊢ (𝑧 ∈ ∩ 𝑥 ∈ 𝐴 𝐶 ↔ ∀𝑥 ∈ 𝐴 𝑧 ∈ 𝐶)
12	9, 11	anbi12i 637	. . . 4 ⊢ ((𝑦 ∈ ∩ 𝑥 ∈ 𝐴 𝐵 ∧ 𝑧 ∈ ∩ 𝑥 ∈ 𝐴 𝐶) ↔ (∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 𝑧 ∈ 𝐶))
13		opelxp 5683	. . . 4 ⊢ (⟨𝑦, 𝑧⟩ ∈ (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶) ↔ (𝑦 ∈ ∩ 𝑥 ∈ 𝐴 𝐵 ∧ 𝑧 ∈ ∩ 𝑥 ∈ 𝐴 𝐶))
14		opex 5431	. . . . . 6 ⊢ ⟨𝑦, 𝑧⟩ ∈ V
15		eliin 4954	. . . . . 6 ⊢ (⟨𝑦, 𝑧⟩ ∈ V → (⟨𝑦, 𝑧⟩ ∈ ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) ↔ ∀𝑥 ∈ 𝐴 ⟨𝑦, 𝑧⟩ ∈ (𝐵 × 𝐶)))
16	14, 15	ax-mp 5	. . . . 5 ⊢ (⟨𝑦, 𝑧⟩ ∈ ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) ↔ ∀𝑥 ∈ 𝐴 ⟨𝑦, 𝑧⟩ ∈ (𝐵 × 𝐶))
17		opelxp 5683	. . . . . 6 ⊢ (⟨𝑦, 𝑧⟩ ∈ (𝐵 × 𝐶) ↔ (𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐶))
18	17	ralbii 3108	. . . . 5 ⊢ (∀𝑥 ∈ 𝐴 ⟨𝑦, 𝑧⟩ ∈ (𝐵 × 𝐶) ↔ ∀𝑥 ∈ 𝐴 (𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐶))
19		r19.26 3122	. . . . 5 ⊢ (∀𝑥 ∈ 𝐴 (𝑦 ∈ 𝐵 ∧ 𝑧 ∈ 𝐶) ↔ (∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 𝑧 ∈ 𝐶))
20	16, 18, 19	3bitri 299	. . . 4 ⊢ (⟨𝑦, 𝑧⟩ ∈ ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) ↔ (∀𝑥 ∈ 𝐴 𝑦 ∈ 𝐵 ∧ ∀𝑥 ∈ 𝐴 𝑧 ∈ 𝐶))
21	12, 13, 20	3bitr4ri 306	. . 3 ⊢ (⟨𝑦, 𝑧⟩ ∈ ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) ↔ ⟨𝑦, 𝑧⟩ ∈ (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶))
22	21	eqrelriv 5761	. 2 ⊢ ((Rel ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) ∧ Rel (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶)) → ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) = (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶))
23	6, 7, 22	sylancl 595	1 ⊢ (𝐴 ≠ ∅ → ∩ 𝑥 ∈ 𝐴 (𝐵 × 𝐶) = (∩ 𝑥 ∈ 𝐴 𝐵 × ∩ 𝑥 ∈ 𝐴 𝐶))

Syntax hints:   → wi 4   ↔ wb 208   ∧ wa 399   = wceq 1560   ∈ wcel 2142   ≠ wne 2957  ∀wral 3076  ∃wrex 3086  Vcvv 3454  ∅c0 4285  ⟨cop 4588  ∩ ciin 4950   × cxp 5645  Rel wrel 5652

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1815  ax-4 1829  ax-5 1930  ax-6 1987  ax-7 2028  ax-8 2144  ax-9 2152  ax-ext 2734  ax-sep 5246  ax-pr 5390

This theorem depends on definitions:  df-bi 209  df-an 400  df-or 859  df-3an 1100  df-tru 1563  df-fal 1573  df-ex 1800  df-sb 2091  df-clab 2741  df-cleq 2754  df-clel 2837  df-ne 2958  df-ral 3077  df-rex 3087  df-rab 3415  df-v 3456  df-dif 3907  df-un 3909  df-in 3911  df-ss 3921  df-nul 4286  df-if 4481  df-sn 4583  df-pr 4585  df-op 4589  df-iin 4952  df-opab 5163  df-xp 5653  df-rel 5654

This theorem is referenced by:  intxp  49450  iinfssclem1  49672