On the rationality of certain strata of the Lange stratification of stable vector bundles on curves.
In [6], orbifold G-bundles on a certain class of elliptic fibrations over a smooth complex projective curve X were related to parabolic G-bundles over X. In this continuation of [6] we define and investigate holomorphic connections on an orbifold G-bundle over an elliptic fibration.
Let be the moduli space of principal -bundles on a curve , and the determinant bundle on . We define an isomorphism of onto the dual of the space of -th order theta functions on the Jacobian of . This isomorphism identifies the rational map defined by the linear system with the map which associates to a quadratic bundle the theta divisor . The two components and of are mapped into the subspaces of even and odd theta functions respectively. Finally we discuss the analogous...
Let be a Galois covering of smooth projective curves with Galois group the Weyl group of a simple and simply connected Lie group . For any dominant weight consider the curve . The Kanev correspondence defines an abelian subvariety of the Jacobian of . We compute the type of the polarization of the restriction of the canonical principal polarization of to in some cases. In particular, in the case of the group we obtain families of Prym-Tyurin varieties. The main idea is the use of...
Given the category of coherent sheaves over a weighted projective line (of any representation type), the endomorphism ring of an arbitrary tilting sheaf - which is by definition an almost concealed canonical algebra - is shown to satisfy a rank additivity property (Theorem 3.2). Moreover, this property extends to the representationinfinite quasi-tilted algebras of canonical type (Theorem 4.2). Finally, it is demonstrated that rank additivity does not generalize to the case of tilting complexes...
In this article, we survey recent work on the construction and geometry of representations of a quiver in the category of coherent sheaves on a projective algebraic manifold. We will also prove new results in the case of the quiver • ← • → •.
We discuss the roots of the Nakayama and Auslander-Reiten translations in the derived category of coherent sheaves over a weighted projective line. As an application we derive some new results on the structure of selfinjective algebras of canonical type.