Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition we correct and extend some results concerning Ki...

We study the problem of Michell trusses when the system of applied equilibrated forces is a vector measure with compact support. We introduce a class of stress tensors which can be written as a superposition of rank-one tensors carried by curves (lines of principal strains). Optimality conditions are given for such families showing in particular that optimal stress tensors are carried by mutual...

Abstract We present a covariant study of static space-times, as such and solutions gravity theories. By expressing the relevant tensors through velocity acceleration vectors that characterise field equations provide natural non-redundant set scalar equations. The same suggest form Faraday tensor, is studied in itself (non)-linear electrodynamics. In spherical symmetry, we evaluate explicit expr...

In this contribution, the use of discrete simulations to formulate an anisotropic damage model is investigated. It proposed a beam–particle perform numerical characterization tests. Indeed, explicitly describes cracking by allowing displacement discontinuities and thus capture crack induced anisotropy quasi-brittle materials such as concrete. Through 2D simulations, evolution effective elastici...

Scalar, vector and tensor conserved quantities are essential tools in solving different problems physics complex, nonlinear differential equations mathematics. In many guises they enter our understanding of nature: charge, lepton, baryon numbers conservation accompanied with constant energy, linear or angular total momenta the energy-momentum/angular momentum tensors field theories due to Noeth...

A bstract We study the classical double copy of massive spinning objects in worldline quantum field theories (WQFT) formalism. couple $$ \mathcal{N} N = 1 supersymmetric model to a Yang-Mills background describe propagation spin-half particle interacting with gluons. At level, this captures physical effects u...

The full geometrical symmetry groups (the line groups) of the monolayered, 2Hb and 3R polytypes of the inorganic MoS2 and WS2 microand nanotubes of arbitrary chirality are found. This is used to find the coordinates of the representative atoms sufficient to determine completely geometrical structure of tubes. Then some physical properties which can be deduced from the symmetry are discussed: el...

The problem discussed in this paper is the symmetric best low multilinear rank approximation of third-order symmetric tensors. We propose an algorithm based on Jacobi rotations, for which symmetry is preserved at each iteration. Two numerical examples are provided indicating the need of such algorithms. An important part of the paper consists of proving that our algorithm converges to stationar...

The solution representing a brane-anti-brane system in matrix models breaks the usual matrix spacetime symmetry. We show that the spacetime symmetry on the branes is not broken, rather appears as a combination of the matrix spacetime transformation and a gauge transformation. As a result, the tachyon field, itself an off-diagonal entry in longitudinal matrices, transforms nontrivially under rot...

The unfolded formulation for arbitrary massless mixed-symmetry bosonic and fermionic fields in Minkowski space is constructed. The unfolded form is proved to be uniquely determined by the requirement that all gauge symmetries are manifest. The unfolded equations have the form of a covariant constancy condition. The gauge fields and gauge parameters are differential forms with values in certain ...