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.
Permanent rector is an obsolete term used in the United States prior to the codification of the 1917 Code of Canon Law. Canon Law grants a type of tenure to pastors (parochus) of parishes, giving them certain rights against arbitrary removal by the bishop of their diocese.