The boundary of a convex set is always a convex curve. The intersection of all convex sets containing a given subset A of Euclidean space is called the convex hull of A. It is the smallest convex set containing A.
Rector (ecclesiastical) A rector is, in an ecclesiastical sense, a cleric who functions as an administrative leader in some Christian denominations, and in Islam. In contrast, a vicar is also a cleric but functions as an assistant and representative of an administrative leader.
Different universities have different governance structures. A provost is usually the top person in charge of education, while the Dean of Faculty would usually be the top professor overseeing the faculty. Then you would have Deans of various schools, like Science and Engineering. Go to any university and look at their organizational or governance chart.