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Metamath Proof Explorer

Theorem subidd

Description: Subtraction of a number from itself. (Contributed by Mario Carneiro, 27-May-2016)

		Ref	Expression
	Hypothesis	negidd.1	$⊢ φ \to A \in ℂ$
	Assertion	subidd	$⊢ φ \to A - A = 0$

Step	Hyp	Ref	Expression
1		negidd.1	$⊢ φ \to A \in ℂ$
2		subid	$⊢ A \in ℂ \to A - A = 0$
3	1 2	syl	$⊢ φ \to A - A = 0$