This paper contains some tentative steps towards describing the structure of non-discrete subgroups of SL(2; R). The main idea is that if a one-parameter family of groups G z varies analytically with the parameter z , then, using analytic continuation, certain results about discrete groups can be analytically continued to those groups in the family that are not discrete. The paper concentrates ...

We investigate two questions about bicrossed products of finite groups which we believe have the potential of being approachable for other classes of algebraic objects. The first one is the problem of classifying groups which can be written as bicrossed products of two groups of fixed isomorphism types and the second is the problem of classifying the groups which cannot be obtained as bicrossed...

We describe fivebrane configurations in M theory whose 4-d spacetime contains N = 1 supersymmetric Sp or SO gauge fields and fundamentals of these groups. We show how fieldtheory dualities for Sp and SO groups can be derived using these fivebrane configurations in M theory. Research Fellow, Miller Institute for Basic Research in Science, 2536 Channing Way, Berkeley, CA 94720 Address after Septe...

We study the M-theory five-brane wrapped around the Seiberg-Witten curves for pure classical and exceptional groups given by an integrable system. Generically, the D4-branes arise as cuts that collapse to points after compactifying the eleventh dimension and going to the semiclassical limit, producing brane configurations of NS5and D4-branes with N = 2 gauge theories on the world volume of the ...

The m-testing of model specification pioneered by Newey (1985) and Tauchen (1985) and extended by White (1987) offers a general framework that unifies many specification tests in the literature. Within the m-testing framework, we consider how to test the hypothesis that a model is correctly specified in each of many groups in the population under study, where each of the groups offers only a fe...

In view of the standard correspondence between transitive groups and certain graphs, this result can be rephrased in the following manner. Let F be a graph which is connected and not complete. Assume that G « Aut F is transitive both on ordered adjacent and non-adjacent pairs of points, and that two non-adjacent points are adjacent to exactly one point. Then T has no triangles, and G and T are ...

We study those (2,m, n)-groups which are almost simple and for which the absolute value of the Euler characteristic is a product of two prime powers. All such groups which are not isomorphic to PSL2(q) or PGL2(q) are completely classified.

Methyl group dynamics of m-xylene was investigated by using incoherent inelastic and quasi-elastic neutron scattering. Inelastic measurements were carried out at the high flux backscattering spectrometer HFBS at the National Institute of Standards, quasi-elastic measurements at the time-of-flight spectrometer NEAT at the Hahn-Meitner-Institute. Rotational potentials are derived which describe t...

Written at the request of GAFA’s Editorial Board, with the goal of explicating some aspects of M. Gromov’s paper [2]. Section 1 recalls the construction of the random group, while section 2 contains a proof that the random group has property (T) based on the ideas from the preprint. The appendix defines CAT(0) spaces and works out in detail some geometric propositions from the preprint used in ...

In the present paper, we give a graph-theoretic description for representatives of all the congruence classes of presentations (or r.c.p. for brevity) for the imprimitive complex reflection groups G(m, 1, n) and G(m, m, n). We have three main results. The first main result is to establish a bijection between the set of all the congruence classes of presentations for the group G(m, 1, n) and the...