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Metamath Proof Explorer

Theorem equcom

Description: Commutative law for equality. Equality is a symmetric relation. (Contributed by NM, 20-Aug-1993)

		Ref	Expression
	Assertion	equcom	$⊢ x = y \leftrightarrow y = x$

Step	Hyp	Ref	Expression
1		equcomi	$⊢ x = y \to y = x$
2		equcomi	$⊢ y = x \to x = y$
3	1 2	impbii	$⊢ x = y \leftrightarrow y = x$