Metamath Proof Explorer


Theorem xaddid2d

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

Ref Expression
Hypothesis xaddid2d.1 φ A *
Assertion xaddid2d φ 0 + 𝑒 A = A

Proof

Step Hyp Ref Expression
1 xaddid2d.1 φ A *
2 xaddid2 A * 0 + 𝑒 A = A
3 1 2 syl φ 0 + 𝑒 A = A