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.
A chancellor is a leader of a university or a college. This title is mainly used in the Commonwealth nations. In other countries, such as the United States, it is more common to call him/her the university president. The chancellor is often just a ceremonial figure. This means he or she does not make many decisions inside the University. He/She is just a person who is chosen to represent the University at official events and with other organizations. In this case, the Chancellor might not even live close to the University or take part in meetings there.