A ring R is defined to be J-normal if for any a, r ∈ R and idempotent e ∈ R, ae = 0 implies Rera ⊆ J (R), where J (R) is the Jacobson radical of R. The class of J-normal rings lies between the classes of weakly normal rings and left min-abel rings. It is proved that R is J-normal if and only if for any idempotent e ∈ R and for any r ∈ R, R(1 − e)re ⊆ J (R) if and only if for any n ≥ 1, the n × n upper triangular matrix ring U n (R) is a J-normal ring if and only if the Dorroh extension of R by Z is J-normal. We show that R is strongly regular if and only if R is J-normal and von Neumann regular. For a J-normal ring R, it is obtained that R is clean if and only if R is exchange. We also investigate J-normality of certain subrings of the ring of 2 × 2 matrices over R.
Mathematics Subject Classification
IntroductionThroughout this work, every ring is associative with identity unless otherwise stated. Recently, some kinds of normality for rings have been investigated in the literature. For instance, the notion of quasi-normality of rings was defined in [13], that is, a ring R is called quasi-normal if ae = 0 implies ea Re = 0 for every nilpotent element a and idempotent e of R. On the other hand, another kind of normality was introduced in [14], namely, a ring R is said to be weakly normal if for all elements a, r and e 2 = e of R, ae = 0 implies that Rera is a nil left ideal of R. It is seen that the notion of a weakly normal ring is a generalization of that of a quasi-normal ring.The Jacobson radical is an important tool for studying the structure of a ring. In the light of aforementioned concepts, it is a reasonable question that what kind of properties does a ring gain when it satisfies normality in terms of its Jacobson radical? This question is one of the motivations to deal with the notion of normality