The identity element of an additive group G, usually denoted 0. In the additive group of vectors, the additive identity is the zero vector 0, in the additive group of polynomials it is the zero polynomial P(x) = 0, in the additive group of m×n matrices it is the m×n zero matrix.

additive group | additive inverse | multiplicative identity | zero | zero matrix | zero polynomial | zero vector