1,697 research outputs found
Packing subgroups in relatively hyperbolic groups
We introduce the bounded packing property for a subgroup of a countable
discrete group G. This property gives a finite upper bound on the number of
left cosets of the subgroup that are pairwise close in G. We establish basic
properties of bounded packing, and give many examples; for instance, every
subgroup of a countable, virtually nilpotent group has bounded packing. We
explain several natural connections between bounded packing and group actions
on CAT(0) cube complexes.
Our main result establishes the bounded packing of relatively quasiconvex
subgroups of a relatively hyperbolic group, under mild hypotheses. As an
application, we prove that relatively quasiconvex subgroups have finite height
and width, properties that strongly restrict the way families of distinct
conjugates of the subgroup can intersect. We prove that an infinite,
nonparabolic relatively quasiconvex subgroup of a relatively hyperbolic group
has finite index in its commensurator. We also prove a virtual malnormality
theorem for separable, relatively quasiconvex subgroups, which is new even in
the word hyperbolic case.Comment: 45 pages, 2 figures. To appear in Geom. Topol. v2: Updated to address
concerns of the referee. Added theorem that an infinite, nonparabolic
relatively quasiconvex subgroup H of a relatively hyperbolic group has finite
index in its commensurator. Added several new geometric results to Section 7.
Theorem 8.9 on packing relative to peripheral subgroups is ne
Towards the Theory of Non--Abelian Tensor Fields I
We present a triangulation--independent area--ordering prescription which
naturally generalizes the well known path ordering one. For such a prescription
it is natural that the two--form ``connection'' should carry three ``color''
indices rather than two as it is in the case of the ordinary one--form gauge
connection. To define the prescription in question we have to define how to
{\it exponentiate} a matrix with three indices. The definition uses the fusion
rule structure constants.Comment: 22 pages, 18 figure
Finiteness properties of cubulated groups
We give a generalized and self-contained account of Haglund-Paulin's
wallspaces and Sageev's construction of the CAT(0) cube complex dual to a
wallspace. We examine criteria on a wallspace leading to finiteness properties
of its dual cube complex. Our discussion is aimed at readers wishing to apply
these methods to produce actions of groups on cube complexes and understand
their nature. We develop the wallspace ideas in a level of generality that
facilitates their application.
Our main result describes the structure of dual cube complexes arising from
relatively hyperbolic groups. Let H_1,...,H_s be relatively quasiconvex
codimension-1 subgroups of a group G that is hyperbolic relative to
P_1,...,P_r. We prove that G acts relatively cocompactly on the associated dual
CAT(0) cube complex C. This generalizes Sageev's result that C is cocompact
when G is hyperbolic. When P_1,...,P_r are abelian, we show that the dual
CAT(0) cube complex C has a G-cocompact CAT(0) truncation.Comment: 58 pages, 12 figures. Version 3: Revisions and slightly improved
results in Sections 7 and 8. Several theorem numbers have changed from the
previous versio
The effect of forest policy on the use of forest resources and forest industry investments in Russia
Application of Finite Elements Method for Improvement of Acoustic Emission Testing
The paper deals with the acoustic emission sensor modeling by means of FEM system COSMOS/M. The following types of acoustic waves in the acoustic emission sensors are investigated: the longitudinal wave and transversal wave. As a material is used piezoelectric ceramics. The computed displacements are compared with physical model under consideration. The results of numerical and physical simulations of the processes of acoustic wave propagation in solebar of the freight-car truck are presented. The fields of dynamic displacements and stresses were calculated for improvement of acoustic emission testing method
On q-deformed gl(l+1)-Whittaker function II
A representation of a specialization of a q-deformed class one lattice
gl(\ell+1}-Whittaker function in terms of cohomology groups of line bundles on
the space QM_d(P^{\ell}) of quasi-maps P^1 to P^{\ell} of degree d is proposed.
For \ell=1, this provides an interpretation of non-specialized q-deformed
gl(2)-Whittaker function in terms of QM_d(\IP^1). In particular the (q-version
of) Mellin-Barnes representation of gl(2)-Whittaker function is realized as a
semi-infinite period map. The explicit form of the period map manifests an
important role of q-version of Gamma-function as a substitute of topological
genus in semi-infinite geometry. A relation with Givental-Lee universal
solution (J-function) of q-deformed gl(2)-Toda chain is also discussed.Comment: Extended version submitted in Comm. Math. Phys., 24 page
Reformulation of Boundary String Field Theory in terms of Boundary State
We reformulate bosonic boundary string field theory in terms of boundary
state. In our formulation, we can formally perform the integration of target
space equations of motion for arbitrary field configurations without assuming
decoupling of matter and ghost. Thus, we obtain the general form of the action
of bosonic boundary string field theory. This formulation may help us to
understand possible interactions between boundary string field theory and the
closed string sector.Comment: 13 page
Kaon photoproduction on the nucleon: Contributions of kaon-hyperon final states to the magnetic moment of the nucleon
By using the Gerasimov-Drell-Hearn (GDH) sum rule and an isobaric model of
kaon photoproduction, we calculate contributions of kaon-hyperon final states
to the magnetic moment of the proton and the neutron. We find that the
contributions are small. The approximation of sigma_{TT'} by sigma_{T} clearly
overestimates the value of the GDH integral. We find a smaller upper bound for
the contributions of kaon-hyperon final states to the proton's anomalous
magnetic moment in kaon photoproduction, and a positive contribution for the
square of the neutron's magnetic moment.Comment: 6 pages, revtex, 1 postscript figure, to appear in Phys. Rev.
On Unification of RR Couplings
We consider the couplings of RR fields with open string sector for
- backgrounds of various . Proposed approach, based on
the approximation of the open string algebra by the algebra of differential
operators, provides the unified description of these couplings and their
interrelations.Comment: References added, Latex, 18 page
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