In mathematics, the convex hull or convex envelope of a set X of points in the Euclidean plane or Euclidean space is the smallest convex set that contains X. For instance, when X is a bounded subset of the plane, the convex hull may be visualized as the shape enclosed by a rubber band stretched around X.Formally, the convex hull may be defined as the intersection of all convex sets containing X or as the set of all convex combinations of points in X.