 Half-spaces (open or closed) are affine convex cones.Moreover (in finite dimensions), any convex cone "C" that is not the whole space "V" must be contained in some closed half-space "H" of "V"; this is a special case of Farkas' lemma.A cone formula_10 is called polyhedral if there is some matrix formula_11 such that formula_12, and a cone formula_10 is called finitely generated if it is the conic combination of finitely many vectors.