On the Griffiths numbers for higher dimensional singularities

We show that Yau's conjecture on the inequalities for (n-1)-th Griffiths number and (n-1)-th Hironaka number does not hold for isolated rigid Gorenstein singularities of dimension greater than 2. But his conjecture on the inequality for (n-1)-th Griffiths number is true for irregular singularities.Comment: to appear in Annales de l'Institut Fourie

Layered identity infrastructure model for identity meta systems

There are several Identity Meta Systems emerging in the identity management field, such as CardSpace and Higgins Trust Framework. The goal of an Identity Meta System (IMetS) is to integrate existing or new Identity Management System (IMS) to provide users with seamless interoperability and a consistent user experience. IMetS is a complex system that tries to integrate the already complicated IMS services. With such a complex system, we need a way to assess IMetS in order to determine how well an IMetS integrates the various IMS services. However, as IMetS is a rela- tively new concept, there is no framework to identify the properties that an ideal IMetS should have. The contribution of this paper is to introduce the Layered Identity Infrastructure Model (LIIM) that can be used as a framework to assess IMetS. In addition, the LIIM framework can also be used to identify the missing components of an IMetS, to guide and improve the design of an existing IMetS, to serve as a design benchmark for a new IMetS, as well as to aid the understanding of a complicated IMetS