Serial rings and subdirect products (Q788085)

Let R be an indecomposable basic generalized uniserial ring. Then R is a subdirect product of factor rings of (S,M)-triangular matrix rings, where S is a local uniserial ring and \(M=rad S\). The author also shows that in the special case, when R is a subdirect product of (S,M)-triangular matrix rings, R has a selfduality. A more general result, however, is true. It was already stated by \textit{I. Amdal} and \textit{F. Ringdal} [C.R. Acad. Sci., Paris, Sér. A 267, 85-87, 247-249 (1968; Zbl 0159.022)] and has recently been proved independently by \textit{W. Müller}, \textit{F. Dischinger} [Arch. Math. (to appear); Zbl 0532.16014)] and by J. Waschbüsch, that every generalized uniserial ring has a selfduality.