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Mostrando ítems 82-101 de 121

    • openAccess   On the existence of non-norm-attaining operators 

      Dantas, Sheldon; Jung, Mingu; Martínez Cervantes, Gonzalo Cambridge University Press (2021-07-09)
      In this article, we provide necessary and sufficient conditions for the existence of non-norm-attaining operators in L(E,F) . By using a theorem due to Pfitzner on James boundaries, we show that if there exists a ...

    • openAccess   On the extreme non-Arens regularity of Banach algebras 

      Filali, Mahmoud; Galindo, Jorge Wiley (2021-07-04)
      As is well-known, on an Arens regular Banach algebra all continuous functionals are weakly almost periodic. In this paper, we show that 1-bases which approximate upper and lower triangles of products of elements in the ...

    • openAccess   On the generalization of the construction of quantum codes from Hermitian self-orthogonal codes 

      Galindo, Carlos; Hernando, Fernando Springer (2022-03-21)
      Many q-ary stabilizer quantum codes can be constructed from Hermitian self-orthogonal q2-ary linear codes. This result can be generalized to q2m-ary linear codes, m>1. We give a result for easily obtaining quantum codes ...

    • openAccess   On using Reproducing Kernel Hilbert Spaces for the analysis of Replicated Spatial Point Processes 

      Simó, Amelia Elsevier (2023)
      This paper focuses on the use of the theory of Reproducing Kernel Hilbert Spaces in the statistical analysis of replicated point processes. We show that spatial point processes can be observed as random variables in a ...

    • openAccess   On various types of density of numerical radius attaining operators 

      Dantas, Sheldon; Kim, Sun Kwang; Lee, Han Ju; Mazzitelli, Martin Taylor and Francis (2023)
      In this paper, we are interested in studying Bishop-Phelps-Bollob´as type properties related to the denseness of the operators which attain their numerical radius. We prove that every Banach space with a micro-transitive ...

    • openAccess   Optimal (r,δ)-LRCs from monomial-Cartesian codes and their subfield-subcodes 

      Galindo, Carlos; Hernando, Fernando; Martín-Cruz, Helena Springer (2024-05-02)
      We study monomial-Cartesian codes (MCCs) which can be regarded as (r,δ)-locally recoverable codes (LRCs). These codes come with a natural bound for their minimum distance and we determine those giving rise to (r,δ)-optimal ...

    • openAccess   Optimal approximation to unitary quantum operators with linear optics 

      Garcia-Escartin, Juan Carlos; Gimeno, Vicent; Moyano-Fernández, Julio José Springer Nature (2021-09-21)
      Linear optical systems acting on photon number states produce many interesting evolutions, but cannot give all the allowed quantum operations on the input state. Using Toponogov’s theorem from differential geometry, we ...

    • openAccess   Order of products of elements in finite groups 

      Beltrán, Antonio; Lyons, Richard; Moretó, Alexander; Navarro, Gabriel; Sáez, Azahara; Tiep, Pham Huu Wiley (2018-10)
      If G is a finite group, p is a prime, and x∈G, it is an interesting problem to place x in a convenient small (normal) subgroup of G, assuming some knowledge of the order of the products xy, for certain p‐elements y of G.

    • openAccess   Orthogonal ℓ1-sets and extreme non-Arens regularity of preduals of von Neumann algebras 

      Filali, Mahmoud; Galindo, Jorge Elsevier (2022-03-04)
      A Banach algebra is Arens-regular when all its continuous functionals are weakly almost periodic, in symbols when ⁎ . To identify the opposite behaviour, Granirer called a Banach algebra extremely non-Arens regular ...

    • openAccess   Phase portraits of Abel quadratic differential systems of the second kind 

      Ferragut, Antoni; Valls, Claudia Taylor & Francis (2018)
      We provide normal forms and the global phase portraits on the Poincaré disk of some Abel quadratic differential equations of the second kind. Moreover, we also provide the bifurcation diagrams for these global phase portraits.

    • openAccess   Pointwise convergence topology and function spaces in fuzzy analysis 

      Jardon, Daniel R.; Sanchis López, Manuel University of Sistan and Baluchestan (2018-03)
      We study the space of all continuous fuzzy-valued functions from a space $X$ into the space of fuzzy numbers $(\mathbb{E}\sp{1},d\sb{\infty})$ endowed with the pointwise convergence topology. Our results generalize the ...

    • openAccess   Preface for the special issue “Geometric numerical integration, twenty-five years later” 

      Blanes, Sergio; Casas, Fernando Taylor and Francis (2023)

    • openAccess   QOptCraft: A Python package for the design and study of linear optical quantum systems 

      Gomez-Aguado, Daniel; Gimeno, Vicent; Moyano-Fernández, Julio José; Garcia-Escartin, Juan Carlos Elsevier (2022-08-29)
      The manipulation of the quantum states of light in linear optical systems has multiple applications in quantum optics and quantum computation. The package QOptCraft gives a collection of methods to solve some of the most ...

    • openAccess   Quasi-cyclic constructions of quantum codes 

      Galindo, Carlos; Hernando, Fernando; Matsumoto, Ryutaroh Elsevier (2018-07)
      We give sufficient conditions for self-orthogonality with respect to symplec- tic, Euclidean and Hermitian inner products of a wide family of quasi-cyclic codes of index two. We provide lower bounds for the symplectic ...

    • openAccess   Reliability Validation of a Low-Cost Particulate Matter IoT Sensor in Indoor and Outdoor Environments Using a Reference Sampler 

      Trilles, Sergio; Vicente, Ana Belen; Juan, Pablo; Ramos, Jose Francisco; Meseguer Costa, Sergio; Serra, Laura MDPI (2019)
      A suitable and quick determination of air quality allows the population to be alerted with respect to high concentrations of pollutants. Recent advances in computer science have led to the development of a high number of ...

    • openAccess   Runge–Kutta–Nyström symplectic splitting methods of order 8 

      Blanes, Sergio; Casas, Fernando; Escorihuela-Tomàs, Alejandro Elsevier (2022-12)
      Different families of Runge–Kutta–Nyström (RKN) symplectic splitting methods of order 8 are presented for second-order systems of ordinary differential equations and are tested on numerical examples. They show a better ...

    • openAccess   [S]-linear and convex structures in function families 

      Bernal González, Luis; Conejero, J. Alberto; murillo arcila, marina; Seoane-Sepúlveda, J. B. Elsevier (2019)
      In this paper, the notion of [S]-lineability (originally coined by Vladimir I. Gurariy) is introduced and developed in a general abstract setting. This new notion is, then, applied to specific situations, as for instance, ...

    • openAccess   Sampling Almost Periodic and Related Functions 

      Ferri, Stefano; Galindo, Jorge; Gómez, Camilo Springer (2020-10)
      We consider certain finite sets of circle-valued functions defined on intervals of real numbers and estimate how large the intervals must be for the values of these functions to be uniformly distributed in an approximate ...

    • openAccess   Sensitive dependence for nonautonomous discrete dynamical systems 

      Miralles Montolío, Alejandro; murillo arcila, marina; Sanchis López, Manuel Elsevier (2018-03)
      Given a nonautonomous discrete dynamical system (NDS) we show that transitivity and density of periodic points do not imply sensitivity in general, i.e., in the definition of Devaney chaos there are no redundant conditions ...

    • openAccess   Seshadri-type constants and Newton-Okounkov bodies for non-positive at infinity valuations of Hirzebruch surfaces 

      Galindo, Carlos; Monserrat, Francisco; Moreno Ávila, Carlos Jesús Taylor and Francis (2023-02-01)
      We consider flags E• = {X ⊃ E ⊃ {q}}, where E is an exceptional divisor defining a non-positive at infinity divisorial valuation νE of a Hirzebruch surface Fδ , q a point in E and X the surface given by νE , and determine ...