Matrix with zero columns multiplied by vector with zero elements yields vector

If evaluating a linear map A on a vector v corresponds to matrix-vector multiplication A * v, then the zero map from \mathbb{R}^2 to \mathbb{R}^0 is represented by zeros(0,2). In contrast, zeros(2,0) is the (zero) map from \mathbb{R}^0 to \mathbb{R}^2 .

2 Likes