Envíos recientes

  • Characterization of principal bundles: the commutative case 

    Ugalde Gómez, William Javier (2023-10-04)
    A review of the characterization of principal bundles, through the different properties of the action of a group and its related canonical and translation maps, is presented. The work is divided in three stages: a topological ...
  • Improved Epstein-Glaser renormalization in x-space versus differential renormalization 

    Gracia Bondía, José M.; Gutiérrez Garro, Heidy; Várilly Boyle, Joseph C. (2014-09)
    Renormalization of massless Feynman amplitudes in x-space is reexamined here, using almost exclusively real-variable methods. We compute a wealth of concrete examples by means of recursive extension of distributions. This ...
  • Metric properties of the fuzzy sphere 

    D'Andrea, Francesco; Lizzi, Fedele; Várilly Boyle, Joseph C. (2013-02)
    The fuzzy sphere, as a quantum metric space, carries a sequence of metrics which we describe in detail. We show that the Bloch coherent states, with these spectral distances, form a sequence of metric spaces that converge ...
  • Testing one-body density functionals on a solvable model 

    Benavides Riveros, Carlos L.; Várilly Boyle, Joseph C. (2012-10)
    There are several physically motivated density matrix functionals in the literature, built from the knowledge of the natural orbitals and the occupation numbers of the one-body reduced density matrix. With the help of the ...
  • The lowest excited configuration of harmonium 

    Benavides Riveros, Carlos L.; Gracia Bondía, José M.; Várilly Boyle, Joseph C. (2012)
    The harmonium model has long been regarded as an exactly solvable laboratory bench for quantum chemistry [W. Heisenberg, Z. Phys. 38, 411 (1926)]. For studying correlation energy, only the ground state of the system has ...
  • Density functional theory on phase space 

    Blanchard, Philippe; Gracia Bondía, José M.; Várilly Boyle, Joseph C. (2012)
    Forty-five years after the point de départ [Hohenberg and Kohn, Phys. Rev. 1964, B864, 136] of density functional theory, its applications in chemistry and the study of electronic structures keep steadily growing. However, ...
  • Wavelet analysis of dengue incidence and its correlation with weather and vegetation variables in Costa Rica 

    García Puerta, Yury Elena; Barboza Chinchilla, Luis Alberto; Sánchez Peña, Fabio Ariel; Vásquez Brenes, Paola Andrea; Calvo Alpízar, Juan Gabriel (2021)
    Dengue represents a serious public health problem in tropical and subtropical regions worldwide. The number of dengue cases and its geographical expansion has increased in recent decades, driven mostly after by social and ...
  • A mathematical model with nonlinear relapse: conditions for a forward-backward bifurcation 

    Sánchez Peña, Fabio Ariel; Arroyo Esquivel, Jorge; Calvo Alpízar, Juan Gabriel (2023)
    We constructed a Susceptible-Addicted-Reformed model and explored the dynamics of nonlinear relapse in the Reformed population. The transition from susceptible considered at-risk is modeled using a strictly decreasing ...
  • Adicción a Redes Sociales: Un Modelo Matemático 

    Garro, Valeria; Masís, Juan J.; Alarcón, Greivin J.; Campos, Camilo D.; Castro, Jorge A.; León, Juan M.; Sánchez Peña, Fabio Ariel (2023)
    El artículo presenta un modelo de dinámica social para el estudio de la adicción a las redes sociales, basado en los modelos matemáticos SIR (Susceptibles-Infectados-Recuperados). El modelo considera cinco categorías de ...
  • Sparse bounds for the discrete spherical maximal function [Presentación] 

    Mena Arias, Darío Alberto (2021-10-24)
    We prove sparse bounds for the spherical maximal operator of Magyar, Stein and Wainger. The bounds are conjecturally sharp, and contain an endpoint estimate. The new method of proof is inspired by ones by Bourgain and ...
  • Sparse bounds for Bochner-Riesz and Maximal Bocher-Riesz 

    Mena Arias, Darío Alberto (2019-06-05)
    The Bochner-Riesz means arise from the study of convergence of Fourier series. Analyzing the behavior of its maximal operator, we can understand its pointwise convergence. We obtain some preliminary results stablishing ...
  • Desarrollo y análisis del comportamiento humano adaptativo en modelos con relapso no lineal 

    Calvo Monge, Jimmy José (2023)
    En este proyecto proponemos estudiar las propiedades teóricas y nuevas aplicaciones de un algoritmo de formulación recuente para modelar las decisiones de contacto humanas en modelos epidemiológicos, que es llamado el ...
  • On the supremum of a family of set functions 

    Cambronero, Santiago; Campos Fernández, José David; Fonseca Mora, Christian Andrés; Mena Arias, Darío Alberto (2023)
    The concept of supremum of a family of set functions was introduced by M. Veraar and I. Yaroslavtsev (2016) for families of measures defined on a measurable space. We expand this concept to include families of set functions ...
  • Quadratic variation for cylindrical martingale-valued measures 

    Cambronero, Santiago; Campos Fernández, José David; Fonseca Mora, Christian Andrés; Mena Arias, Darío Alberto (2023)
    This article focuses in the definition of a quadratic variation for cylindrical orthogonal martingale-valued measures defined on Banach spaces. Sufficient and necessary conditions for the existence of such a quadratic ...
  • The Sparse T1 Theorem [presentación] 

    Mena Arias, Darío Alberto; Lacey, Michael T. (2017-03)
  • Lacunary discrete spherical maximal functions 

    Kesler, Robert; Lacey, Michael T.; Mena Arias, Darío Alberto (2019)
    We prove new l^p(Z^d) bounds for discrete spherical averages in dimensions d greater than or equal to 5. We focus on the case of lacunary radii, first for general lacunary radii, and then for certain kinds of highly ...
  • Characterization of two-parameter matrix valued BMO by commutator with the Hilbert Transform 

    Mena Arias, Darío Alberto (2018)
    In this paper, we prove that the space of two parameter matrix-valued BMO functions can be characterized by considering iterated commutators with the Hilbert transform. The upper estimate relies on Petermichl's representation ...
  • The Sparse T1 Theorem 

    Lacey, Michael T.; Mena Arias, Darío Alberto (2017)
    We impose standard T1-type assumptions on a Calderon-Zygmund operator T, and deduce that for bounded compactly supported functions f and g there is a sparse bilinear form B so that |< Tf, g >|; < B(f,g). The proof is short ...
  • Twofold Saddle-Point Formulation of Biot Poroelasticity with Stress-Dependent Diffusion 

    Gómez Vargas, Bryan Andrés; Mardal, Kent André; Ruiz Baier, Ricardo; Vinje, Vegard (2023)
    We present a new stress/total-pressure formulation for poroelasticity that incorporates the coupling with steady nonlinear diffusion modified by stress. This nonlinear problem is written in mixed-primal form, which combines ...
  • A nonlinear relapse model with disaggregated contact rates: Analysis of a forward-backward bifurcation 

    Calvo Monge, Jimmy José; Sánchez Peña, Fabio Ariel; Calvo Alpízar, Juan Gabriel; Mena Arias, Darío Alberto (2023-09)
    Throughout the progress of epidemic scenarios, individuals in different health classes are expected to have different average daily contact behavior. This contact heterogeneity has been studied in recent adaptive models ...

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