Theorem mullidd

Description: Identity law for multiplication. (Contributed by Mario Carneiro, 27-May-2016)

	Ref	Expression
Hypothesis	addcld.1	$$⊢\phi \to A\in ℂ$$
Assertion	mullidd	$$⊢\phi \to 1A=A$$

Proof

Step	Hyp	Ref	Expression
1		addcld.1	$$⊢\phi \to A\in ℂ$$
2		mullid	$$⊢A\in ℂ\to 1A=A$$
3	1 2	syl	$$⊢\phi \to 1A=A$$