Double centralizer theorem

In the branch of abstract algebra called ring theory, the double centralizer theorem can refer to any one of several similar results. These results concern the centralizer of a subring S of a ring R, denoted CR(S) in this article. It is always the case that CR(CR(S)) contains S, and a double centralizer theorem gives conditions on R and S that guarantee that CR(CR(S)) is equal to S.

This keyword could refer to multiple things. Here are some suggestions: