ISSN:0075-4102    

DOI:10.1515/crll.1999.506.1

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

AbstractThe motion of any smooth closed convex curve in the plane in the direction of steepest increase of its affine arc length can be continued smoothly for all time. The evolving curve remains strictly convex while expanding to infinite size and approaching a homothetically expanding ellipse.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.43

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

RésuméOn se propose de donner une forme effective au théorème de Mazur-Kamienny-Merel sur la torsion des courbes elliptiques sur les corps de nombres.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.85

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

AbstractWe give a new proof of a theorem of Siu and Trautmann on the vanishing of cohomology with support on complex or rigid analytic spaces. We indicate how our methods might be used to prove various comparison theorems in algebraic and analytic geometry.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.117

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

AbstractIn this work we develop new techniques to compute Koszul cohomology groups for several classes of varieties. As applications we prove results on projective normality and syzygies for algebraic surfaces. From more general results we obtain in particular the following:Mukai's conjecture (and stronger variants of it) regarding projective normality and normal presentation for surfaces with Kodaira dimension 0, and uniform bounds for higher syzygies associated to adjoint linear series,effective bounds along the lines of Mukai's conjecture regarding projective normality and normal presentation for surfaces of positive Kodaira dimension, and,results on projective normality for pluricanonical models of surfaces of general type (recovering and strengthening results by Ciliberto) and generalizations of them to higher syzygies.In addition, we also extend the above results to singular surfaces.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.145

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

AbstractWe introduce the canonical outer derivation (or vector field) on a Poisson manifold. This is a Poisson vector field well-defined modulo hamiltonian vector fields.We study this outer derivation by geometric and sheaf-theoretic methods, mostly for holomorphic Poisson manifolds.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.181

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

AbstractWe solve the matrix-valued Nevanlinna-Pick problem in the space of bounded analytic functions on the bidisk, and give a description of all the interpolating functions. We also prove the Toeplitz-corona theorem on the bidisk.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.191

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

摘要:

AbstractIt is proved that every minimal surface with one or two boundary components in a simply connected Riemannian manifold with sectional curvature bounded above by a nonpositive constantKsatisfies the sharp isoperimetric inequality 4πA≦L2+K A2. Here equality holds if and only if the minimal surface is a geodesic disk in a surface of constant Gaussian curvatureK.

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.205

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter

ISSN:0075-4102    

DOI:10.1515/crll.1999.506.215

出版商:Walter de Gruyter    

年代:1999

数据来源: Degruyter