let $h$, $l$ and $x$ be subgroups of a finite group$g$. then $h$ is said to be $x$-permutable with $l$ if for some$xin x$ we have $al^{x}=l^{x}a$. we say that $h$ is emph{$x$-quasipermutable } (emph{$x_{s}$-quasipermutable}, respectively) in $g$ provided $g$ has a subgroup$b$ such that $g=n_{g}(h)b$ and $h$ $x$-permutes with $b$ and with all subgroups (with all sylowsubgroups, respectively) $v$...

The lattice of flats of a matroid or combinatorial geometry can be regarded as a sublattice (with rank function) of the lattice of subsets of a set, having the property that, given an element of rank r of the lattice and a point outside it, a unique element of rank r+1 covers both. This paper develops a theory of permutation geometries, which are similarly defined objects in the semilattice of ...

The aim of this paper is to study the actions of the groups on lattices and to give some connections between the structure of a group and the structure of its subgroup lattice. Moreover, we shall introduce the concept of direct ∨-sum of G-sublattices and we shall present a generalization of a result about finite nilpotent groups. 1 Preliminaries Let (G, ·, e) be a monoid and L be a G–set (relat...

Introduction In the theory of groups, the important concepts of Abelian group, solvable group, nilpotent group, the center of a group and centraliz-ers, are all defined from the binary operation [x, y] = x −1 y −1 xy. Each of these notions, except centralizers of elements, may also be defined in terms of the commutator of normal subgroups. The commutator [M, N] (where M and N are normal subgrou...

Let H be a group, let {G(: i e 1} be a set of groups and, for each i, let 9t be a a monomorphism: H -* Gt, with H9t = Hi. We call such a system of groups and monomorphisms an amalgam and denote it by [G{; H; 9,; / / , ] . By an embedding of the amalgam into a group G is meant a set of monomorphisms (p; : G; -*• G such that 9i<pi = 0j<Pj-, for all i,j and G,<P; n Gjcpj — H9k<pk, for all i,j, k. ...

Abstract We prove sharp upper and lower bounds for generalized Calderón’s sums associated to frames on LCA groups generated by affine actions of cocompact subgroup translations and general measurable families of automorphisms. The proof makes use of techniques of analysis on metric spaces, and relies on a counting estimate of lattice points inside metric balls. We will deduce as special cases C...

In this paper we derive an explicit formula for the HirzebruchMumford volume of an even lattice L of signature (2, n). If Γ ⊂ O(L) is an arithmetic subgroup, then an application of Hirzebruch-Mumford proportionality allows us to determine the leading term of the growth of the dimension of the spaces Sk(Γ) of cusp forms of weight k, as k goes to infinity. We compute this in a number of examples,...

Let M = 〈M, +, <, 0, S〉 be a linear o-minimal expansion of an ordered group, and G = 〈G,⊕, eG〉 an n-dimensional group definable in M. We show that if G is definably connected with respect to the t-topology, then it is definably isomorphic to a definable quotient group U/L, for some convex ∨ definable subgroup U of 〈Mn, +〉 and a lattice L of rank equal to the dimension of the ‘compact part’ of G.

The continuous Lorentz symmetry is broken to a discrete subgroup–but the internal (gauge) symmetry is preserved. Note that it is this feature that renders the study of lattice supersymmetry so non-trivial, since supersymmetry mixes Lorentz symmetry and internal symmetry in a non-trivial way. In quantum mechanics we consider functions that take values in phase space. These functions are valued i...

We continue the program, presented in previous Symposia, of discretizing physical models. In particular we calculate the integral Lorentz transformations with the help of discrete reflection groups, and use them for the covariance of Klein-Gordon and Dirac wave equation on the lattice. Finally we define the unitary representation of Poincaré group on discrete momentum and configuration space, i...