Communications in Algebra, 2025 (SCI-Expanded)
Rings all of whose right ideals are automorphism-invariant are called right a-rings. It is shown that (Formula presented.) local right a-rings are left duo, (Formula presented.) local rings whose left ideals of R are invariant under all units of R are left duo, (Formula presented.) a right a-ring R with (Formula presented.) is duo. In this paper, the question of when is a left a-ring a right a-ring is also addressed. It is shown that (Formula presented.) if R is a quasi-Frobenius ring or right (or left) noetherian/artinian ring, then R is a right a-ring if and only if R is a left a-ring. It is also proved that (Formula presented.) R is a right a-ring with ACC on right annihilators iff R is a left a-ring with ACC on left annihilators, questions (partially) answering the different question on this topic.