Ray of a fan
= Ray of a fan
= Toric ray
{synonym}
A <ray of a fan> is a one-dimensional cone in a <fan in toric geometry>. It has the form $\mathbb R_{\geq0}v$, where $v$ is a primitive <lattice> vector, and occurs as a <face of a polyhedral cone>.
A ray of a fan is a one-dimensional cone. It has a unique primitive lattice generator $v_\rho$ pointing along it.