Weakly normal rings.

A ring R is defined to be weakly normal if for all a, r ∈ R and e ∈ E(R), ae = 0 implies Rera is a nil left ideal of R, where E(R) stands for the set of all idempotent elements of R. It is proved that R is weakly normal if and only if Rer(1 -- e) is a nil left ideal of R for each e ∈ E(R) and r ∈ R if and only if Tn(R, R) is weakly normal for any positive integer n. And it follows that for a weakly normal ring R (1) R is Abelian if and only if R is strongly left idempotent reflexive; (2) R is reduced if and only if R is n-regular; (3) R is strongly regular if and only if R is regular; (4) R is clean if and only if R is exchange. (5) exchange rings have stable range 1. [ABSTRACT FROM AUTHOR]