207 research outputs found
Hilbert forms for a Finsler metrizable projective class of sprays
The projective Finsler metrizability problem deals with the question whether
a projective-equivalence class of sprays is the geodesic class of a (locally or
globally defined) Finsler function. In this paper we use Hilbert-type forms to
state a number of different ways of specifying necessary and sufficient
conditions for this to be the case, and we show that they are equivalent. We
also address several related issues of interest including path spaces, Jacobi
fields, totally-geodesic submanifolds of a spray space, and the equivalence of
path geometries and projective-equivalence classes of sprays.Comment: 23 page
The multiplier approach to the projective Finsler metrizability problem
This paper is concerned with the problem of determining whether a
projective-equivalence class of sprays is the geodesic class of a Finsler
function. We address both the local and the global aspects of this problem. We
present our results entirely in terms of a multiplier, that is, a type (0,2)
tensor field along the tangent bundle projection. In the course of the analysis
we consider several related issues of interest including the positivity and
strong convexity of positively-homogeneous functions, the relation to the
so-called Rapcs\'ak conditions, some peculiarities of the two-dimensional case,
and geodesic convexity for sprays.Comment: 25 page
Invariant Lagrangians, mechanical connections and the Lagrange-Poincare equations
We deal with Lagrangian systems that are invariant under the action of a
symmetry group. The mechanical connection is a principal connection that is
associated to Lagrangians which have a kinetic energy function that is defined
by a Riemannian metric. In this paper we extend this notion to arbitrary
Lagrangians. We then derive the reduced Lagrange-Poincare equations in a new
fashion and we show how solutions of the Euler-Lagrange equations can be
reconstructed with the help of the mechanical connection. Illustrative examples
confirm the theory.Comment: 22 pages, to appear in J. Phys. A: Math. Theor., D2HFest special
issu
The Berwald-type linearisation of generalised connections
We study the existence of a natural `linearisation' process for generalised
connections on an affine bundle. It is shown that this leads to an affine
generalised connection over a prolonged bundle, which is the analogue of what
is called a connection of Berwald type in the standard theory of connections.
Various new insights are being obtained in the fine structure of affine bundles
over an anchored vector bundle and affineness of generalised connections on
such bundles.Comment: 25 page
The inverse problem for Lagrangian systems with certain non-conservative forces
We discuss two generalizations of the inverse problem of the calculus of
variations, one in which a given mechanical system can be brought into the form
of Lagrangian equations with non-conservative forces of a generalized Rayleigh
dissipation type, the other leading to Lagrangian equations with so-called
gyroscopic forces. Our approach focusses primarily on obtaining coordinate-free
conditions for the existence of a suitable non-singular multiplier matrix,
which will lead to an equivalent representation of a given system of
second-order equations as one of these Lagrangian systems with non-conservative
forces.Comment: 28 page
Isometries, submetries and distance coordinates on Finsler manifolds
This paper considers fundamental issues related to Finslerian iso-
metries, submetries, distance and geodesics. It is shown that at each
point of a Finsler manifold there is a distance coordinate system. Us-
ing distance coordinates, a simple proof is given for the Finslerian
version of the Myers-Steenrod theorem and for the differentiability of
Finslerian submetries
A setting for higher order differential equations fields and higher order Lagrange and Finsler spaces
We use the Fr\"olicher-Nijenhuis formalism to reformulate the inverse problem
of the calculus of variations for a system of differential equations of order
2k in terms of a semi-basic 1-form of order k. Within this general context, we
use the homogeneity proposed by Crampin and Saunders in [14] to formulate and
discuss the projective metrizability problem for higher order differential
equation fields. We provide necessary and sufficient conditions for higher
order projectivpre-e metrizability in terms of homogeneous semi-basic 1-forms.
Such a semi-basic 1-form is the Poincar\'e-Cartan 1-form of a higher order
Finsler function, while the potential of such semi-basic 1-form is a higher
order Finsler function.Comment: final, pre-published versio
Veliparib in Combination With Platinum-Based Chemotherapy for First-Line Treatment of Advanced Squamous Cell Lung Cancer: A Randomized, Multicenter Phase III Study
Prospects for at CERN in NA62
The NA62 experiment will begin taking data in 2015. Its primary purpose is a
10% measurement of the branching ratio of the ultrarare kaon decay , using the decay in flight of kaons in an unseparated
beam with momentum 75 GeV/c.The detector and analysis technique are described
here.Comment: 8 pages for proceedings of 50 Years of CP
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