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.
In the wider picture of ecclesiastical polity, a parish comprises a division of a diocese or see. Parishes within a diocese may be grouped into a deanery or vicariate forane (or simply vicariate), overseen by a dean or vicar forane, or in some cases by an archpriest.