DefinitionIn abstract algebra, ring theory is the study of rings-algebraic structures in which addition and multiplication are defined and have similar properties to those operations defined for the integers. Rings are a generalization of the integers (with the addition of a+b, the multiplication of a*b, and where a*1 is a for every integer a), and include structures like fields and polynomial rings. Example: the ring of all 2×2 matrices with real number entries under matrix addition and multiplication.