剩余交和一般剩余交的几个性质

本文给出了剩余交和一般剩余交的几个性质，主要讨论了剩余交的ＧＣＭ性和在形变下的变化情况，并讨论了一般剩余交的ＧＣＭ性，ＣＭ性和可光滑性等．     

连锁类的几个不变性质

给出了连锁类的几个不变性质,得到：在ＣＭ局部环中,广义ＣＭ性是连锁类的不变性质;强广义ＣＭ性是偶连锁类的不变性质;在正则局部环中,余维数ｋ≤３可光滑性是连锁类的不变性质。     

On tangential deformations of homogeneous polynomials

The Jacobian ideal provides the set of infinitesimally trivial deformations for a homogeneous polynomial, or for the corresponding complex projective hypersurface. In this article, we investigate whether the associated linear deformation is indeed trivial, and show that the answer is no in a general situation. We also give a characterization of tangentially smoothable hypersurfaces with isolated singularities. Our results have applications in the local study of variations of projective hypersurfaces, complementing the global versions given by J. Carlson and P. Griffiths, R. Donagi and the author, and in the study of isotrivial linear systems on the projective space, showing that a general divisor does not belong to an isotrivial linear system of positive dimension.     

Smoothable zero dimensional schemes and special projections of algebraic varieties

We study the degrees of generators of the ideal of a projected Veronese variety to depending on the center of projection. This is related to the geometry of zero dimensional schemes of length 8 in , Cremona transforms of , and the geometry of Tonoli Calabi‐Yau threefolds of degree 17 in .     

Further Results on the Smoothability of Cauchy Hypersurfaces and Cauchy Time Functions

Recently, folk questions on the smoothability of Cauchy hypersurfaces and time functions of a globally hyperbolic spacetime M, have been solved. Here we give further results, applicable to several problems: