We give lower bounds for the slope of higher dimensional fibrations f : X → B over curves under conditions of GIT-semistability of the fibres, using a generalization of a method of Cornalba and Harris. With the same method we establish a sharp lower bound for the slope of trigonal fibrations of even genus and general Maroni invariant; in particular this result proves a conjecture due to Harris and Stankova-Frenkel.
Slopes of trigonal fibred surfaces and of higher dimensional fibrations
STOPPINO, LIDIA
2009-01-01
Abstract
We give lower bounds for the slope of higher dimensional fibrations f : X → B over curves under conditions of GIT-semistability of the fibres, using a generalization of a method of Cornalba and Harris. With the same method we establish a sharp lower bound for the slope of trigonal fibrations of even genus and general Maroni invariant; in particular this result proves a conjecture due to Harris and Stankova-Frenkel.File | Dimensione | Formato | |
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