Metamath Proof Explorer


Theorem xaddlidd

Description: 0 is a left identity for extended real addition. (Contributed by Glauco Siliprandi, 17-Aug-2020)

Ref Expression
Hypothesis xaddlidd.1 φA*
Assertion xaddlidd φ0+𝑒A=A

Proof

Step Hyp Ref Expression
1 xaddlidd.1 φA*
2 xaddlid A*0+𝑒A=A
3 1 2 syl φ0+𝑒A=A