The ring of integers is the set of integers ..., -2, -1, 0, 1, 2, ..., which form a ring. This ring is commonly denoted Z (doublestruck Z), or sometimes I (doublestruck I). More generally, let K be a number field. Then the ring of integers of K, denoted O_K, is the set of algebraic integers in K, which is a ring of dimension d over Z, where d is the extension degree of K over Q. O_K is also sometimes called the maximal order of K.

algebraic integer | Eisenstein integer | extension field degree | Gaussian integer | I | integer | maximal order | number field | number field order | ring | Z