A ug 2 00 7 EXISTENCE OF QUASI - ARCS

1 4 A ug 2 00 7 THE ASYMPTOTIC GEOMETRY OF RIGHT - ANGLED ARTIN GROUPS , I

We study atomic right-angled Artin groups – those whose defining graph has no cycles of length ≤ 4, and no separating vertices, separating edges, or separating vertex stars. We show that these groups are not quasi-isometrically rigid, but that an intermediate form of rigidity does hold. We deduce from this that two atomic groups are quasi-isometric iff they are isomorphic.

1 4 A ug 2 00 7 THE ASYMPTOTIC GEOMETRY OF RIGHT - ANGLED ARTIN GROUPS

We study atomic right-angled Artin groups – those whose defining graph has no cycles of length ≤ 4, and no separating vertices, separating edges, or separating vertex stars. We show that these groups are not quasi-isometrically rigid, but that an intermediate form of rigidity does hold. We deduce from this that two atomic groups are quasi-isometric iff they are isomorphic.

m at h . FA ] 1 8 A ug 2 00 1 On normed products of operator ideals which contain L 2 as a factor

We investigate quasi-Banach operator ideal products (A ◦ B,A ◦ B) which contain (L2,L2) as a factor. In particular, we ask for conditions which guarantee that A ◦ B is even a norm if each factor of the product is a 1-Banach ideal. In doing so, we reveal the strong influence of the existence of such a norm in relation to the accessibility of the product ideal and the structure of its factors.

A ug 2 00 6 Quasi - Lie structure of σ - derivations of C [ t ± 1 ]

Role of Initial Data in Higher Dimensional Quasi-Spherical Gravitational Collapse

X iv :g rqc /0 30 80 37 v1 1 2 A ug 2 00 3 Role of Initial Data in Higher Dimensional Quasi-Spherical Gravitational Collapse Ujjal Debnath and Subenoy Chakraborty Department of Mathematics, Jadavpur University, Calcutta-32, India. (Dated: February 7, 2008) We study the gravitational collapse in (n+2)-D quasi-spherical Szekeres space-time (which possess no killing vectors) with dust as the matte...