Theorem iuneq12dOLD 4990

Description: Obsolete version of iuneq12d 4991 as of 1-Sep-2025. (Contributed by Drahflow, 22-Oct-2015.) (Proof modification is discouraged.) (New usage is discouraged.)

Hypotheses

Ref	Expression
iuneq1d.1	⊢ (𝜑 → 𝐴 = 𝐵)
iuneq12dOLD.2	⊢ (𝜑 → 𝐶 = 𝐷)

Assertion

Ref	Expression
iuneq12dOLD	⊢ (𝜑 → ∪ 𝑥 ∈ 𝐴 𝐶 = ∪ 𝑥 ∈ 𝐵 𝐷)

Distinct variable groups:   𝑥,𝐴   𝑥,𝐵   𝜑,𝑥

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

Proof of Theorem iuneq12dOLD

Step	Hyp	Ref	Expression
1		iuneq1d.1	. . 3 ⊢ (𝜑 → 𝐴 = 𝐵)
2	1	iuneq1d 4989	. 2 ⊢ (𝜑 → ∪ 𝑥 ∈ 𝐴 𝐶 = ∪ 𝑥 ∈ 𝐵 𝐶)
3		iuneq12dOLD.2	. . . 4 ⊢ (𝜑 → 𝐶 = 𝐷)
4	3	adantr 486	. . 3 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → 𝐶 = 𝐷)
5	4	iuneq2dv 4986	. 2 ⊢ (𝜑 → ∪ 𝑥 ∈ 𝐵 𝐶 = ∪ 𝑥 ∈ 𝐵 𝐷)
6	2, 5	eqtrd 2801	1 ⊢ (𝜑 → ∪ 𝑥 ∈ 𝐴 𝐶 = ∪ 𝑥 ∈ 𝐵 𝐷)

This proof depends on syntax axioms:   → wi 4   = wceq 1570   ∈ wcel 2146  ∪ ciun 4961

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-ext 2738

This proof depends on definitions:  df-bi 210  df-an 402  df-tru 1573  df-ex 1813  df-sb 2100  df-clab 2745  df-cleq 2758  df-clel 2841  df-ral 3083  df-rex 3093  df-v 3460  df-ss 3925  df-iun 4963

This theorem is used by: (None)