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

[Benny]

@fph

Consider the function such that f(x) = 0 for each x\in \mathbb{R}^2.

Wouldn’t that be a map from \mathbb{R}^2 to \mathbb{R}^1 e.g. 0a+0b=0 meaning [0 0]*[a, b] == [0]?