Infinitesimal variations of hodge structure (I)
Let a smooth projective family and a pseudo-effective line bundle on (i.e. with a non-negative curvature current ). In its works on invariance of plurigenera, Y.-T. Siu was interested in extending sections of (defined over the central fiber of the family ) to sections of . In this article we consider the following problem: to extend sections of . More precisely, we show the following result: assuming the triviality of the multiplier ideal sheaf , any section of extends to ; in other...
We prove an extension theorem of Ohsawa-Takegoshi type for line bundle sections on a subvariety of general codimension in a normal projective variety. Our method of proof gives conditions to be satisfied for such extension in a general setting, while such conditions are satisfied when the subvariety is given by an appropriate multiplier ideal sheaf.
Given a positive singular hermitian metric of a pseudoeffective line bundle on a complex Kähler manifold, a singular foliation is constructed satisfying certain analytic analogues of numerical conditions. This foliation refines Tsuji’s numerically trivial fibration and the Iitaka fibration. Using almost positive singular hermitian metrics with analytic singularities on a pseudo-effective line bundle , a foliation is constructed refining the nef fibration. If the singularities of the foliation are...
Second order elliptic systems with boundary conditions of Dirichlet, Neumann’s or Newton’s type are solved by means of linear finite elements on regular uniform triangulations. Error estimates of the optimal order are proved for the averaged gradient on any fixed interior subdomain, provided the problem under consideration is regular in a certain sense.