Theory of (1+1) ES on SPHERE Revisited

Es-13854 1..11

Civil engineering is changing and needs to change more. This paper attempts to put the evolution of technology and the development of engineering into its historical context, and with it the emergence of problems whose solutions extend beyond technology alone if they are to achieve systems-level solutions. The balancing of economic, social and environmental objectives, both now and into the fut...

Relative Equilibria of Point Vorti es on the Sphere

Sphere packings revisited

In this paper we survey most of the recent and often surprising results on packings of congruent spheres in d-dimensional spaces of constant curvature. The topics discussed are as follows: Hadwiger numbers of convex bodies and kissing numbers of spheres; Touching numbers of convex bodies; Newton numbers of convex bodies; One-sided Hadwiger and kissing numbers; Contact graphs of finite packings ...

Contact graphs of unit sphere packings revisited

The contact graph of an arbitrary finite packing of unit balls in Euclidean 3-space is the (simple) graph whose vertices correspond to the packing elements and whose two vertices are connected by an edge if the corresponding two packing elements touch each other. One of the most basic questions on contact graphs is to find the maximum number of edges that a contact graph of a packing of n unit ...

D=11 Supergravity Revisited

I discuss two novel results in D=11 Supergravity. The first establishes, in two complementary ways, a no-go theorem that, in contrast to all D<11, a cosmological extension of the theory does not exist. The second deals with the structure of (on-shell) four-point invariants. These are important both for establishing existence of the lowest (2-loop) order candidate counter-terms in the theory pro...