Abstract: | Let σ be a Dedekind ring, let σ be a maximal order in a quadratic extension K of the field k of quotients of the ring σ, let Λ be a subring of the ring σ, containing σ and such that ΛK=K. It is proved that σ/Λ is a cyclic Λ-module. From here there follows, in particular, that each finitely generated torsion-free Λ-module is a direct sum of modules which are isomorphic to the ideals of ring Λ. Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 160, pp. 262, 1987. |