Metamath Proof Explorer


Theorem addlidd

Description: 0 is a left identity for addition. (Contributed by Mario Carneiro, 27-May-2016)

Ref Expression
Hypothesis muld.1 φA
Assertion addlidd φ0+A=A

Proof

Step Hyp Ref Expression
1 muld.1 φA
2 addlid A0+A=A
3 1 2 syl φ0+A=A