The paper studies discrete structural properties of polynomials that play an important role in the theory of spherical harmonics in any dimensions. These polynomials have their origin in the research on problems of ha...
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In this paper we define the property of feasible reachability both for 1D state-space systems evolving over Z and for 2D state-space systems evolving over Z 2 described by Fornasini-Marchesini models. Feasible reachab...
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In this paper we define the property of feasible reachability both for 1D state-space systems evolving over Z and for 2D state-space systems evolving over Z 2 described by Fornasini-Marchesini models. Feasible reachability consists in the reachability of the feasible subspaces associated with those systems. After characterizing these properties in terms of the system matrices, we compare them with behavioral controllability.
作者：
João P. A. NovoDepartamento de Matemática
Universidade de Aveiro and Center for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-193 Aveiro Portugal
In Newtonian gravity, it is well known that Kepler’s problem admits no bound solutions in more than three spatial dimensions. This limitation extends naturally to General Relativity, where Tangherlini demonstrated th...
In Newtonian gravity, it is well known that Kepler’s problem admits no bound solutions in more than three spatial dimensions. This limitation extends naturally to General Relativity, where Tangherlini demonstrated that Schwarzschild black holes in higher dimensions admit no bound timelike geodesics. However, an analogous result for the rotating counterpart of the five-dimensional Tangherlini spacetime—the d=5 Myers-Perry black hole—has not yet been established. This work addresses this gap by proving that no bound timelike geodesics exist outside the event horizon of a d=5 Myers-Perry black hole, for any choice of spin parameters that avoid naked singularities. With this result in place, we further generalize to null geodesics. It is shown that radially bound null geodesics, which are absent in the four-dimensional Kerr spacetime as established by Wilkins, also cannot exist in the d=5 Myers-Perry spacetime. These results complete the geodesic analysis of this spacetime and provide a direct generalization of Wilkins’s classical result to higher dimensions. Specifically, we establish the following theorem: no radially bound timelike nor null geodesics are possible outside the event horizon of a d=5 Myers-Perry black hole, regardless of the spin configuration.
Starting with a symmetric monoidal adjunction with certain properties, we derive another symmetric monoidal adjunction with the same properties between the respective categories of all V-categories. If we begin with a...
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Given the difficulty of attaining strategic competitive advantages in today’s business environment, particularly in the automotive industry, the quality of the processes involved in a production line is becoming incr...
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Given the difficulty of attaining strategic competitive advantages in today’s business environment, particularly in the automotive industry, the quality of the processes involved in a production line is becoming increasingly crucial. In this context, Industry 4.0, which is closely linked to the evolution of information systems, is key, since it enables a more efficient result analysis and enhances the decision-making process for managers. Also, continuous improvement is a fundamental philosophy to help companies deal with quality issues and thus become more competitive. In this work, the developed program, that allows users to register the quality problems found in a production line, is presented. This new program contributes to maintaining an accurate record of the quality issues identified, as well as facilitates the analysis of those situations by the managers. The results observed showed that it was possible to reduce several wastes, leading to a significant impact in the organization.
This paper mainly focuses on solving the Ulam–Hyers and Ulam–Hyers–JRassias stability problem of the linear delay differential equation using Aboodh transform technique. In addition, the results are extended to inv...
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Determining physical properties inside an object without access to direct measurements of target regions can be formulated as a specific type of inverse problem. One of such problems is applied in Electrical Impedance...
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We study the bifurcation phenomena between spherical and axisymmetric bosonic stars. By numerically solving for the zero-modes of spherical bosonic stars under specific axially symmetric perturbations, we discover tha...
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It is shown that the reflection 2Cat → 2Preord of the category of all 2-categories into the category of 2-preorders determines a monotone-light factorization system on 2Cat and that the light morphisms are precisely ...
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We study stationary clouds of a gauged, complex scalar field on a magnetically (and possibly electrically as well) charged Kerr-Newman black hole (BH). The existence of a magnetic charge Qm promotes a north-south asym...
We study stationary clouds of a gauged, complex scalar field on a magnetically (and possibly electrically as well) charged Kerr-Newman black hole (BH). The existence of a magnetic charge Qm promotes a north-south asymmetry of the scalar clouds. This breakdown of the clouds’ Z2-symmetry carries through to the spacetime geometry for the nonlinear continuation of the clouds: a family of magnetically charged (or dyonic) BHs with synchronized gauged scalar hair, which we construct. Their distinct phenomenology is illustrated by their imaging, exhibiting skewed shadows and lensing. Such hairy BHs could, in principle, result from the superradiant instability of magnetically charged Kerr-Newman BHs, unveiling a dynamical mechanism for creating north-south asymmetric BHs from standard Z2-symmetric electrovacuum BHs.
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