For questions relating to the mathematical or geometric structure known as a cone.
Let $\bf x$ be an $n$-dimensional vector in $\Bbb R^n$. A set $C\in\Bbb R^n$ is a cone if the product $a{\bf x}\in C$ for all $a\ge0$ and all $x\in C$.
Learn more: Wikipedia Cone page and Wikipedia Convex Cone page.