I have a hard time understanding why the author go out of his/her way to rename standard definitions.<p>1. The definition of convex hull of a set S in the article, is the boundary of a convex set that contains all the points in S. The standard definition is the "intersection of all convex sets that contains S".
Edit: Yes, this is not a good definition for the article, but there is a equivalent for finite set of points in 2D which is much better suited: "The smallest convex polygon contain all the points in S"<p>2. The definition of minimal convex hull in the article, in the standard terminology, is the boundary of the convex hull.<p>The article links to wikipedia which clearly explains what is a convex hull, but still decides to come up with new terminology. As a warning, the "convex hull" in this article is not equivalent to the "convex hull" in wikipedia(or any other textbook definitions I have seen).