Search results for "JOINT"
showing 10 items of 1472 documents
Non linear representations of Lie Groups
1977
International audience
The graded Lie algebra structure of Lie superalgebra deformation theory
1989
We show how Lie superalgebra deformation theory can be treated by graded Lie algebras formalism. Rigidity and integrability theorems are obtained.
Analytic Bergman operators in the semiclassical limit
2018
Transposing the Berezin quantization into the setting of analytic microlocal analysis, we construct approximate semiclassical Bergman projections on weighted $L^2$ spaces with analytic weights, and show that their kernel functions admit an asymptotic expansion in the class of analytic symbols. As a corollary, we obtain new estimates for asymptotic expansions of the Bergman kernel on $\mathbb{C}^n$ and for high powers of ample holomorphic line bundles over compact complex manifolds.
Markov extensions for multi-dimensional dynamical systems
1999
By a result of F. Hofbauer [11], piecewise monotonic maps of the interval can be identified with topological Markov chains with respect to measures with large entropy. We generalize this to arbitrary piecewise invertible dynamical systems under the following assumption: the total entropy of the system should be greater than the topological entropy of the boundary of some reasonable partition separating almost all orbits. We get a sufficient condition for these maps to have a finite number of invariant and ergodic probability measures with maximal entropy. We illustrate our results by quoting an application to a class of multi-dimensional, non-linear, non-expansive smooth dynamical systems.
On non-self-adjoint operators defined by Riesz bases in Hilbert and rigged Hilbert spaces
2018
In this paper we discuss some results on non self-adjoint Hamiltonians with real discrete simple spectrum under the assumption that their eigenvectors form Riesz bases of a certain Hilbert space. Also, we exhibit a generalization of those results to the case of rigged Hilbert spaces, and we also consider the problem of the factorization of the aforementioned Hamiltonians in terms of generalized lowering and raising operators.
Scattering resonances and Pseudospectrum : stability and completeness aspects in optical and gravitational systems
2022
The general context of this thesis is an effort to establish a bridge between gravitational andoptical physics, specifically in the context of scattering problems using as a guideline concepts andtools taken from the theory of non-self-adjoint operators. Our focus is on Quasi-Normal Modes(QNMs), namely the natural resonant modes of open leaky structures under linear perturbationssubject to outgoing boundary conditions. They also are referred to as scattering resonances.In the conservative self-adjoint case the spectral theorem guarantees the completeness andspectral stability of the associated normal modes. In this sense, a natural question in the non-self-adjoint setting refers to the char…
static optimal estimation of joint accelerations for inverse dynamics problem solution
2002
In inverse dynamics computations, the accuracy of the solution strongly depends on the accuracy of the input data. In particular, estimated joint moments are highly sensitive to uncertainties in acceleration data. The aim of the present work was to improve classical inverse dynamics computations by providing an accurate estimation of accelerations. Accelerations are usually calculated from noise-polluted position data using numerical double differentiation, which amplifies measurement noise. The objective of the present paper is to use all available imperfect position and force measurements to extract optimum acceleration estimations. A weighted least-squares optimisation approach is used t…
The relationship between non-audit fees and audit quality: dealing with the endogeneity issue
2015
Purpose – The purpose of this paper is to explore whether the provision of non-audit services (NAS) by public accounting firms undermines audit quality. The study addresses this question by testing for an association between the provision of consulting services and auditor independence in listed companies. Design/methodology/approach – The authors study if the magnitude of non-audit fees explains variations in earnings management by looking at the joint determination of non-audit fees, audit fees, and abnormal accruals using the SURE-regression estimation method. Findings – Evidence from tested models suggests that audit services quality is uncompromised by the provision of NAS. In other w…
Revisiting the regulation of auditor independence: Spanish evidence on different perceptions
2012
Following the dramatic financial scandals at the turn of the millennium, the financial system reporting framework has changed considerably to restore confidence among investors. In 2002, Spain was one of the pioneer EU member countries to regulate audit quality and protect auditor independence. In the specific setting of Spain, the objective of this research is to obtain evidence that can contribute to the debate on whether there is a need for regulation in this field. In this sense, we find evidence on the existence of an expectations gap between two groups of agents affected by the important changes that the 2002 rules on independence and audit quality imposed on auditors, i.e., the audit…
Reviewing a Friend - The Role of Social Ties in Review Work in Auditing
2016
Hierarchically structured review work is a pervasive element in many professional work settings, including auditing. However, little is known about social factors underlying the pairing of reviewers and reviewees and their impact on quality. The German auditing setting provides a unique opportunity to empirically observe review work at the highest hierarchical level. We investigate the role of social ties in the pairing of concurring auditor (reviewer) and lead auditor (reviewee). We find that the presence of social ties between the concurring auditor and the lead auditor resulting from local affinity, i.e., having the same dialect and working in the same office, makes it more likely for th…