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Metamath Proof Explorer

Theorem unieqi

Description: Inference of equality of two class unions. (Contributed by NM, 30-Aug-1993)

		Ref	Expression
	Hypothesis	unieqi.1	$⊢ A = B$
	Assertion	unieqi	$⊢ ⋃ A = ⋃ B$

Step	Hyp	Ref	Expression
1		unieqi.1	$⊢ A = B$
2		unieq	$⊢ A = B \to ⋃ A = ⋃ B$
3	1 2	ax-mp	$⊢ ⋃ A = ⋃ B$