1,721,155 research outputs found
On algebraic curves whose osculating planes belong to the maximal number of independent linear complexes
No full textQregularity and an Extension of Evans-Griffiths Criterion to Vector Bundles on Quadrics
No full textAbstractHere we define the concept of Qregularity for coherent sheaves on a smooth quadric hypersurface Qn⊂Pn+1. In this setting we prove analogs of some classical properties. We compare the Qregularity of coherent sheaves on Qn with the Castelnuovo–Mumford regularity of their extension by zero in Pn+1. We also classify the coherent sheaves with Qregularity −∞. We use our notion of Qregularity in order to prove an extension of the Evans–Griffiths criterion to vector bundles on quadrics. In particular, we get a new and simple proof of Knörrer’s characterization of ACM bundles
Nodal curves and postulation of generic fat points on P^2
No full textWe study the postulation of a general union Z of fat points of P2, when
most of the connected components of Z have multiplicity 2. This problem is related to the existence of 'good' families of curves on P2 with prescribed singularities, most of them being nodes, and to the cohomology of suitable line bundles on blowing ups of th
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