An algebraic annulus theorem

An Algebraic Annulus Theorem

This result has also been proved by Bowditch [2], using very different methods. We discuss these differences at the end of this introduction. The terminology used is standard (from [11] and [17]). The importance of splitting groups along infinite cyclic subgroups is well known from the work of Paulin [13], Rips and Sela [14] and Sela [18]. If G has an infinite cyclic subgroup H such that e(G,H)...

A ug 1 99 6 An algebraic annulus theorem G . P . Scott and

We present an extension of Dunwoody's theory of tracks and use it to prove an analogue of the annulus theorem for hyperbolic groups.

Halin's theorem for cubic graphs on an annulus

An algebraic approach to Halls matching theorem

The purpose of this note is to present a proof of Hall's matching theorem (also called marriage theorem) which I have not encountered elsewhere in literature-what yet does not mean that it is necessarily new. We refer to Hall's theorem in the following form: Theorem 1 (Hall). Let n be a positive integer. Let be a bipartite graph whose set of vertices consists of n blue vertices B 1 ; B 2 Some n...

An Algebraic Spin and Statistics Theorem

A spin-statistics theorem and a PCT theorem are obtained in the context of the superselection sectors in Quantum Field Theory on a 4-dimensional space-time. Our main assumption is the requirement that the modular groups of the von Neumann algebras of local observables associated with wedge regions act geometrically as pure Lorentz transformations. Such a property, satissed by the local algebras...