ar X iv : m at h / 03 10 05 6 v 2 [ m at h . C O ] 5 M ay 2 00 4 COMPLEXES OF GRAPH HOMOMORPHISMS

ar X iv : m at h / 03 10 05 6 v 3 [ m at h . C O ] 2 6 A ug 2 00 4 COMPLEXES OF GRAPH HOMOMORPHISMS

Hom (G,H) is a polyhedral complex defined for any two undirected graphs G and H. This construction was introduced by Lovász to give lower bounds for chromatic numbers of graphs. In this paper we initiate the study of the topological properties of this class of complexes. We prove that Hom (Km,Kn) is homotopy equivalent to a wedge of (n−m)dimensional spheres, and provide an enumeration formula f...

ar X iv : m at h / 03 05 20 7 v 4 [ m at h . D S ] 6 M ay 2 00 6 Lipschitz Flow - box Theorem

A generalization of the Flow-box Theorem is proven. The assumption of a C vector field f is relaxed to the condition that f be locally Lipschitz. The theorem holds in any Banach space.

ar X iv : h ep - p h / 04 05 03 9 v 1 5 M ay 2 00 4 η , η ′ → π + π − γ with coupled channels

ar X iv : m at h / 03 11 05 9 v 1 [ m at h . O A ] 5 N ov 2 00 3 ON THE ASYMPTOTIC TENSOR NORM

We introduce a new asymptotic one-sided and symmetric tensor norm, the latter of which can be considered as the minimal tensor norm on the category of separable C *-algebras with homotopy classes of asymptotic homomorphisms as morphisms. We show that the one-sided asymptotic tensor norm differs in general from both the minimal and the maximal tensor norms and discuss its relation to semi-invert...

ar X iv : h ep - p h / 03 05 16 5 v 1 1 5 M ay 2 00 3 The rise and fall of F 2 at low x

A short personal account is given of the impact of HERA data and the influence of Jan Kwiecinski on low x physics.