Definition:Center (Abstract Algebra)/Ring

Definition
The center of a ring $\struct {R, +, \circ}$, denoted $\map Z R$, is the subset of elements in $R$ that commute under $\circ$ with every element in $R$.

Symbolically:
 * $\map Z R = \map {C_R} R = \set {x \in R: \forall s \in R: s \circ x = x \circ s}$

That is, the center of $R$ is the centralizer of $R$ in $R$ itself.

It is clear that the center of a ring $\struct {R, +, \circ}$ can be defined as the center of the semigroup $\struct {R, \circ}$.

Also see

 * Definition:Centralizer of Ring Subset