A real square matrix A{\displaystyle A} is monotone (in the sense of Collatz) if for all real vectors v{\displaystyle v}, Av≥0{\displaystyle Av\geq 0} implies v≥0{\displaystyle v\geq 0}, where ≥{\displaystyle \geq } is the element-wise order on Rn{\displaystyle \mathbb {R} ^{n}}.