37 research outputs found
On smooth surfaces in projective four-space lying on quartic hypersurfaces with isolated singularities
We prove that a smooth surface, non of general type, in projective
four-space, which lies on a quartic hypersurface with isolated singularities
has degree at most 27 (in fact we prove a slightly more general result)
On Buchsbaum bundles on quadric hypersurfaces
Let be an indecomposable rank two vector bundle on the projective space
\PP^n, n \ge 3, over an algebraically closed field of characteristic zero. It
is well known that is arithmetically Buchsbaum if and only if and
is a null-correlation bundle. In the present paper we establish an analogous
result for rank two indecomposable arithmetically Buchsbaum vector bundles on
the smooth quadric hypersurface Q_n\subset\PP^{n+1}, . We give in
fact a full classification and prove that must be at most 5. As to
-Buchsbaum rank two vector bundles on , , we prove two
boundedness results.Comment: 22 pages, no figur