Recession cone
= Recession cone
{title2=$\operatorname{rec}(P)=\{d:Ad\le0\}$}
The recession cone of a nonempty <convex set> $C$ consists of directions $d$ for which $x+td\in C$ for every $x\in C$ and $t\ge0$. For a <linear polyhedron> $P=\{x:Ax\le b\}$ it is exactly $\{d:Ad\le0\}$. A nonzero recession direction gives an unbounded ray, so a bounded nonempty polyhedron has recession cone $\{0\}$. This excludes spurious zero-scale feasible points in the <Charnes-Cooper transformation>.