Quasipolar Property of Generalized Matrix Rings

The article concerns the question of when a generalized matrix ring K s (R) over a local ring R is quasipolar. For a commutative local ring R, it is proved that K s (R) is quasipolar if and only if it is strongly clean. For a general local ring R, some partial answers to the question are obtained. There exist noncommutative local rings R such that K s (R) is strongly clean, but not quasipolar. Necessary and sufficient conditions for a single matrix of K s (R) (where R is a commutative local ring) to be quasipolar is obtained. The known results on this subject in [5] are improved or extended.