Search results for "GEOMETRIA"

On a result of L.-C. Kappe and M. Newell

2009

There is a long line of research investigating upper central series of a group. The interest comes from the information which these series can give on the structure of a group. Baer (1952) extended the usual notion of center of a group, introducing that of p-centre, where p is a prime. Almost 40 years later, Kappe and Newell (1989) were able to embed the p-centre of a metabelian p-group in the p-th term of the upper central series. This was possible because of the growing knowledge on Engel groups of the 60s years. Here we extend the result of Kappe and Newell (1989) to wider classes of groups.

A note about additive designs

2008

Topologie à l'infini et variétés à géométrie bornée

2013

We give a quick review on the asymptotic topology and the geometry of manifolds with bounded geometry, by quoting also some results obtained by the authors.

A counterexample to a conjecture on linear systems on ℙ3

2004

In this paper [1] Ciliberto proposes a conjecture in order to characterize special linear systems of IPn through multiple base points. In this note we give a counterexample to this conjecture by showing that there is a substantial difference between the speciality of linear systems on IP 2 and those of IP3.

The action of the unitary group associated with a quadratic extension of fields

1999

Given a quadratic extension L/k of fields of characteristic different from 2 and a unitary space (V, f) of finite dimension over L, we give a representation, as simple as possible, of the form which f induces by restriction on a k-substructure of V. This, in turn, allows one to study the orbits of the unitary group U(V, f) in the set of k-substructures of V of a given dimension.

On Geometric Simple Connectivity

2010

L'articolo intende dare una visione panoramica su ricerche recenti, molte delle quali sono da attribuire al V.Poenaru, sulla topologia di dimensione basse e sulla teoria geometrica dei gruppi.

MR 3219513 Reviewed Venkataramana T. N. Monodromy of cyclic coverings of the projective line. Invent. Math., 197 (2014), 1–-45. (Reviewer Francesca V…

2014

Let $d \geq 2$ and $n \geq 1$ be integers and $P_{n+1}$ be the pure braid group on $n + 1$ strands. In this paper, the author studies the image of $P_{n+1}$ under the monodromy action on the homology of a cyclic covering of degree $d$ of the projective line. More precisely, let $k_{1}, \ldots, k_{n + 1}$ be integers such that $1 \leq k_{i} \leq d - 1$ and gcd$(k_{i}, d) = 1$ for each $i$. Moreover, let $a_{1}, \ldots, a_{n + 1}$ be distinct points of the complex plane and $C$ be the space of points in $\mathbb{C}^{n + 1}$ with all distinct coordinates. Let us denote by $X_{a, k}$ the affine curve defined by the equation $$ y^{d} = (x - a_{1})^{k_{1}} (x - a_{2})^{k_{2}} \cdots (x - a_{n +1}…

A short survey on isoperimetric problem on non compact Riemannian manifolds

2009

In this text, we explain some known results about isoperimetric profile of complete smooth noncompact Riemannian manifolds of dimension 2, with one end, with two ends and with more than two ends.

MadeInMath

2016

Wielandt's results for algebraic k-groups

2006

We analyze the relation between subnormality and nilpotence, the subnormal joint property, some criteria of subnormality, the norm and the Wielandt subgroup in the case of algebraic groups defined over an arbitrary field.