SUMMARYMany production Grid and e-Science infrastructures have begun to offer services to end-users during the past several years with an increasing number of scientific applications that require access to a wide variety of resources and services in multiple Grids. Therefore, the Grid Interoperation Now-Community Group of the Open Grid Forum-organizes and manages interoperation efforts among those production Grid infrastructures to reach the goal of a world-wide Grid vision on a technical level in the near future. This contribution highlights fundamental approaches of the group and discusses open standards in the context of production e-Science infrastructures.

The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the international effort towards computing for the Large Hadron Collider. The project, funded by the UK Particle Physics and Astronomy Research Council (PPARC), began in September 2001 and completed its first phase 3 years later. GridPP is a collaboration of approximately 100 researchers in 19 UK university particle physics groups, the Council for the Central Laboratory of the Research Councils and CERN, reflecting the strategic importance of the project. In collaboration with other European and US efforts, the first phase of the project demonstrated the feasibility of developing, deploying and operating a Grid-based computing system to meet the UK needs of the Large Hadron Collider experiments. This note describes the work undertaken to achieve this goal. S Supplementary documentation is available from stacks.iop.org/JPhysG/32/N1. References to sections S1, S2.1, etc are to sections within this online supplement.

We calculate explicitly the character of some indecomposable tilting modules for Ž. SL K where K is a field of characteristic p) 2.

The Certification Authority Coordination Group in the European DataGrid project has created a large-scale Public Key Infrastructure and the policies and procedures to operate it successfully. The infrastructure demonstrates interoperability of multiple certification authorities (CAs) in a novel system of peer-assessment of the roots of trust. Crucial to the assessment is the definition of minimum requirements that all CAs must meet in order to be accepted. The evaluation is aided by software-generated trust matrices. Related work building on this infrastructure is described. The group's policies and experience now form the basis of the new European Policy Management Authority for Grid Authentication in e-Science.

The National Grid Service (NGS) provides access to compute and data resources for UK academics. Currently users are required to have an X.509 certificate from the UK eScience Certification Authority (CA) or one of its international peers to access the NGS. The CA must satisfy the requirements for internationally agreed assurance levels and some users find the processes of obtaining and managing certificates difficult. Shibboleth, an implementation of federation identity-based authentication, has been widely deployed in academic environments in the UK. The SARoNGS project, was proposed to integrate the Shibboleth and X.509 based infrastructures, to deliver a production level service for accessing the NGS in a user-friendly way. This paper describes an architecture by which users are authenticated by the UK Access Management Federation to acquire low assurance credentials to access Grid resources on the NGS. Users can login to NGS resources via NGS Portal, using their local institution's authentication system.