Theorem iuneqconst 4959

Description: Indexed union of identical classes. (Contributed by AV, 5-Mar-2024.)

Hypothesis

Ref	Expression
iuneqconst.p	⊢ (𝑥 = 𝑋 → 𝐵 = 𝐶)

Assertion

Ref	Expression
iuneqconst	⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → ∪ 𝑥 ∈ 𝐴 𝐵 = 𝐶)

Distinct variable groups:   𝑥,𝐴   𝑥,𝐶   𝑥,𝑋

Allowed substitution hint:   𝐵(𝑥)

Proof of Theorem iuneqconst

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		eliun 4951	. . 3 ⊢ (𝑦 ∈ ∪ 𝑥 ∈ 𝐴 𝐵 ↔ ∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵)
2		iuneqconst.p	. . . . . . . 8 ⊢ (𝑥 = 𝑋 → 𝐵 = 𝐶)
3	2	eleq2d 2823	. . . . . . 7 ⊢ (𝑥 = 𝑋 → (𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶))
4	3	rspcev 3577	. . . . . 6 ⊢ ((𝑋 ∈ 𝐴 ∧ 𝑦 ∈ 𝐶) → ∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵)
5	4	adantlr 716	. . . . 5 ⊢ (((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) ∧ 𝑦 ∈ 𝐶) → ∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵)
6	5	ex 412	. . . 4 ⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → (𝑦 ∈ 𝐶 → ∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵))
7		nfv 1916	. . . . . 6 ⊢ Ⅎ𝑥 𝑋 ∈ 𝐴
8		nfra1 3261	. . . . . 6 ⊢ Ⅎ𝑥∀𝑥 ∈ 𝐴 𝐵 = 𝐶
9	7, 8	nfan 1901	. . . . 5 ⊢ Ⅎ𝑥(𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶)
10		nfv 1916	. . . . 5 ⊢ Ⅎ𝑥 𝑦 ∈ 𝐶
11		rsp 3225	. . . . . . 7 ⊢ (∀𝑥 ∈ 𝐴 𝐵 = 𝐶 → (𝑥 ∈ 𝐴 → 𝐵 = 𝐶))
12		eleq2 2826	. . . . . . . 8 ⊢ (𝐵 = 𝐶 → (𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶))
13	12	biimpd 229	. . . . . . 7 ⊢ (𝐵 = 𝐶 → (𝑦 ∈ 𝐵 → 𝑦 ∈ 𝐶))
14	11, 13	syl6 35	. . . . . 6 ⊢ (∀𝑥 ∈ 𝐴 𝐵 = 𝐶 → (𝑥 ∈ 𝐴 → (𝑦 ∈ 𝐵 → 𝑦 ∈ 𝐶)))
15	14	adantl 481	. . . . 5 ⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → (𝑥 ∈ 𝐴 → (𝑦 ∈ 𝐵 → 𝑦 ∈ 𝐶)))
16	9, 10, 15	rexlimd 3244	. . . 4 ⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → (∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵 → 𝑦 ∈ 𝐶))
17	6, 16	impbid 212	. . 3 ⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → (𝑦 ∈ 𝐶 ↔ ∃𝑥 ∈ 𝐴 𝑦 ∈ 𝐵))
18	1, 17	bitr4id 290	. 2 ⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → (𝑦 ∈ ∪ 𝑥 ∈ 𝐴 𝐵 ↔ 𝑦 ∈ 𝐶))
19	18	eqrdv 2735	1 ⊢ ((𝑋 ∈ 𝐴 ∧ ∀𝑥 ∈ 𝐴 𝐵 = 𝐶) → ∪ 𝑥 ∈ 𝐴 𝐵 = 𝐶)

Syntax hints:   → wi 4   ∧ wa 395   = wceq 1542   ∈ wcel 2114  ∀wral 3052  ∃wrex 3061  ∪ ciun 4947

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1912  ax-6 1969  ax-7 2010  ax-8 2116  ax-9 2124  ax-10 2147  ax-12 2185  ax-ext 2709

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-tru 1545  df-ex 1782  df-nf 1786  df-sb 2069  df-clab 2716  df-cleq 2729  df-clel 2812  df-ral 3053  df-rex 3062  df-v 3443  df-iun 4949

This theorem is referenced by:  uniimafveqt  47663  imasetpreimafvbijlemfv  47684