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Metamath Proof Explorer

Theorem undm

Description: De Morgan's law for union. Theorem 5.2(13) of Stoll p. 19. (Contributed by NM, 18-Aug-2004)

		Ref	Expression
	Assertion	undm	$⊢ V ∖ (A \cup B) = (V ∖ A) \cap (V ∖ B)$

Step	Hyp	Ref	Expression
1		difundi	$⊢ V ∖ (A \cup B) = (V ∖ A) \cap (V ∖ B)$