Special Effect Varieties and (−1)-curves
نویسنده
چکیده
Here we introduce the concept of special effect curve which permits to study, from a different point of view, special linear systems in P, i.e. linear system with general multiple base points whose effective dimension is strictly greater than the expected one. In particular we study two different kinds of special effect: the α−special effect is defined by requiring some numerical conditions, while the definition of h−special effect concerns cohomology groups. We state two new conjectures for the characterization of special linear systems and we prove they are equivalent to the Segre and the Harbourne-Hirschowitz ones.
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