Group-theoretical aspects of instantons

Ends—group Theoretical and Topological Aspects

This is a survey of topological, group theoretical and some graph theoretical aspects of ends. After discussing the notion of ends in topology, we consider ends of graphs and show that the metric end topology of connected graphs is metrizable. The “1–2–Cantor theorem” is proved for graphs whose ends are all limit ends, that is, ends which are accumulation points of an orbit of the group of auto...

Instantons: topological aspects

Group-Theoretical Aspects of Orbifold and Conifold GUTs

Motivated by the simplicity and direct phenomenological applicability of field-theoretic orbifold constructions in the context of grand unification, we set out to survey the immensely rich group-theoretical possibilities open to this type of model building. In particular, we show how every maximal-rank, regular subgroup of a simple Lie group can be obtained by orbifolding and determine under wh...

Group Signatures: Better Efficiency and New Theoretical Aspects

A group signature scheme allows members of a group to sign messages anonymously. To counter misuse, the so-called group manager can revoke the anonymity. This paper contributes two results to the area of group signatures. First, we improve the state-of-theart scheme by Ateniese et al. by an order of magnitude. Our new scheme satisfies the recent security definition by Bellare et al. Second, and...

Theoretical aspects of immunity.

The immune system recognizes a myriad of invading pathogens and their toxic products. It does so with a finite repertoire of antibodies and T cell receptors. We here describe theories that quantify the dynamics of the immune system. We describe how the immune system recognizes antigens by searching the large space of receptor molecules. We consider in some detail the theories that quantify the ...