Ring of the Fisherman cardinal. Ring of the Fisherman The Ring of the Fisherman (Latin: "Annulus Piscatoris"; Italian: "Anello Piscatorio"), also known as the Piscatory Ring, is an official part of the regalia worn by the Pope, who is head of the Catholic Church and successor of Saint Peter who was a fisherman by trade. It used to feature a bas-relief of Peter fishing from a boat, a symbolism derived from the tradition that the apostles were "fishers of men" (Mark 1:17). The Fisherman's Ring is a signet used until 1842 to seal official documents signed by the Pope. A letter written by Pope
Partially ordered ring a ring "A" to the set of its non-negative elements is one-to-one; that is, the compatible partial order uniquely determines the set of non-negative elements, and a set of elements uniquely determines the compatible partial order if one exists. If "S" is a subset of a ring "A", and: then the relation formula_1 where formula_2 iff formula_24 defines a compatible partial order on "A" ("ie." formula_8 is a partially ordered ring). In any l-ring, the "absolute value" formula_26 of an element "x" can be defined to be formula_27, where formula_28 denotes the maximal element. For any "x" and "y", holds.