Boundary slopes (nearly) bound cyclic slopes.
We prove that the natural map from bounded to usual cohomology is injective if is an irreducible cocompact lattice in a higher rank Lie group. This result holds also for nontrivial unitary coefficients, and implies finiteness results for : the stable commutator length vanishes and any –action on the circle is almost trivial. We introduce the continuous bounded cohomology of a locally compact group and prove our statements by relating to the continuous bounded cohomology of the ambient group...
This work concerns bounds for Chern classes of holomorphic semistable and stable vector bundles on . Non-negative polynomials in Chern classes are constructed for 4-vector bundles on and a generalization of the presented method to r-bundles on is given. At the end of this paper the construction of bundles from complete intersection is introduced to see how rough the estimates we obtain are.
We estimate the characteristic rank of the canonical –plane bundle over the oriented Grassmann manifold . We then use it to compute uniform upper bounds for the –cup-length of for belonging to certain intervals.
Laminations are classic sets of disjoint and non-self-crossing curves on surfaces. Lamination languages are languages of two-way infinite words which code laminations by using associated labeled embedded graphs, and which are subshifts. Here, we characterize the possible exact affine factor complexities of these languages through bouquets of circles, i.e. graphs made of one vertex, as representative coding graphs. We also show how to build families of laminations together with corresponding lamination...
On étudie les morphismes d’un groupe infini discret dans un groupe de Lie contenu dans le groupe des difféomorphismes de la droite réelle. À un tel morphisme , on associe deux ensembles de “bouts” de “dans la direction” . On calcule le nombre de bouts dans plusieurs situations. Dans le cas particulier où est de type fini et où est le groupe des translations, n’a qu’un bout dans la direction si, et seulement si, ils vérifient la propriété de Bieri-Neumann-Strebel.
These are the notes from a one-week course on Braid Monodromy of Algebraic Curves given at the Université de Pau et des Pays de l’Adour during the Première Ecole Franco-Espagnole: Groupes de tresses et topologie en petite dimension in October 2009.This is intended to be an introductory survey through which we hope we can briefly outline the power of the concept monodromy as a common area for group theory, algebraic geometry, and topology of projective curves.The main classical results are stated...