# Math Help - Center of a Ring and an Ideal

1. ## Center of a Ring and an Ideal

When is the center of a ring Z(R) an ideal of R?

2. Originally Posted by olgaviolet
When is the center of a ring Z(R) an ideal of R?
It's only an ideal when $\mathcal{Z}(R)=R$ since $1\in\mathcal{Z}(R)$, or are you talking about non-unital rings?

3. We havent learned about non-unital rings. I am not sure what they are.
thank you

4. non-unital rings are rings that do not possess a mutliplicative identity element. an example is the ring 2Z.