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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11799

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2010 - 201829

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Data inicial: 2010Data final: 2018

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Agora exibindo 1 - 10 de 29
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    How to break the uniqueness of W1,ploc(Ω)Wloc1,p(Ω) -solutions for very singular elliptic problems by non-local terms
    (Zeitschrift für angewandte Mathematik und Physik, 2018-12) Santos, Carlos Alberto; Santos, Lais
    In this paper, we are going to show existence of branches of bifurcation of positive W1,ploc(Ω)Wloc1,p(Ω) -solutions for the very singular non-local λλ -problem −⎛⎝⎜∫Ωg(x,u)dx⎞⎠⎟rΔpu=λ(a(x)u−δ+b(x)uβ) in Ω,u>0 in Ω and u=0 on ∂Ω, −(∫Ωg(x,u)dx)rΔpu=λ(a(x)u−δ+b(x)uβ) in Ω,u>0 in Ω and u=0 on ∂Ω, where Ω⊂RNΩ⊂RN is a smooth bounded domain, δ>0δ>0 , 0<β
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    The ϕ-Dimension: A new homological measure
    (Algebras and Representation Theory, 2015-04) Fernandes, Sônia Maria; Lanzilotta, Marcelo; Hernández, Octavio Mendoza
    In Igusa and Todorov (2005) introduced two functions ϕ and ψ, which are natural and important homological measures generalising the notion of the projective dimension. These Igusa-Todorov functions have become a powerful tool to understand better the finitistic dimension conjecture. In this paper, for an artin R-algebra A and the Igusa-Todorov function ϕ, we characterise the ϕ-dimension of A in terms of the bi-functors ExtiA(−,−)ExtAi(−,−) and in terms of Tor’s bi-functors TorAi(−,−).ToriA(−,−). Furthermore, by using the first characterisation of the ϕ-dimension, we show that the finiteness of the ϕ-dimension of an artin algebra is invariant under derived equivalences. As an application of this result, we generalise the classical Bongartz’s result (Bongartz, Lect. Notes Math. 903, 26–38, (1981), Corollary 1) as follows: For an artin algebra A, a tilting A-module T and the endomorphism algebra B = End A (T) o p , we have that ϕ dim (A) − pd T ≤ ϕ dim (B) ≤ ϕ dim (A) + pd T.
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    Generalized edge-pairings for the family of hyperbolic tessellations {10λ,2λ}
    (Computational and Applied Mathematics, 2016-04) Faria, Mercio Botelho; Vieira, Vandenberg Lopes; Palazzo Jr., Reginaldo
    In this paper we present generalized edge-pairings for the family of hyperbolic tessellations {10λ,2λ}{10λ,2λ} , with the purpose to obtain the corresponding discrete group of isometries. These tessellations have greater density packing than the self-dual tessellations {4λ,4λ}{4λ,4λ} implying that the associated codes achieve the least error probability, or equivalently, that these codes are optimum codes.
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    Stabilization of mixture of two rigid solids modeling temperature and porosity
    (Applied Mathematics Letters, 2012-05) Alves, Margareth S.; Rivera, Jaime E. Muñoz; Sepúlveda, Mauricio; Villagrán, Octavio P. Vera
    In this paper we investigate the asymptotic behavior of solutions to the initial boundary value problem for a mixture of two rigid solids modeling temperature and porosity. Our main result is to establish conditions which ensure the analyticity and the exponential stability of the corresponding semigroup.
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    Renormalization and forcing of horseshoe orbits
    (Topology and its Applications, 2014-08-15) Mendoza, Valentín
    In this paper we deal with the Boyland forcing of horseshoe orbits. We prove that there exists a set R of renormalizable horseshoe orbits containing only quasi-one-dimensional orbits, that is, for these orbits the Boyland order coincides with the unimodal order.
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    Mathematical analysis of a model for plant invasion mediated by allelopathy
    (Ecological Complexity, 2014-06) Fassoni, A. C.; Martins, M. L.
    Exotic plants threaten the biodiversity of natural habitats and the integrity of agricultural systems throughout the World. Therefore, understanding, predicting and controlling plant invasions became issues of great practical importance. In the present paper, a model for plant invasion based on allelopathic suppression is proposed and studied through analytical methods and numerical integration. Employing linear stability analysis the conditions for plant coexistence as well as one species extinction were determined for the spatially homogeneous system. These conditions demonstrate the advantage conferred to the alien plant by its phytotoxin. It was shown that the system exhibits bistability between two distinct fixed points, either associated to species coexistence or to the extinction of one species. Numerical simulation is also included to support such results. Further, the invasion spreading starting from a single, spatially localized initial focus was investigated by numerical integration of the model's equations. As obtained for the spatially homogeneous system, at strong interspecific competition the outcome is the extinction of one plant species. In contrast, at low interspecific competition, the rule is the coexistence between the invader and native plants. So, under weak competition alien species can invade, but genetic diversity can be sustained.
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    Uniform stabilization for the transmission problem of the Timoshenko system with memory
    (Journal of Mathematical Analysis and Applications, 2010-09-01) Alves, Margareth S.; Raposo, Carlos Alberto; Rivera, Jaime E. Muñoz; Sepúlveda, Mauricio A.; Villagrán, Octavio Paulo Vera
    In this paper we study the transmission for a partially viscoelastic beam, that is, a beam which is composed of two components, elastic and viscoelastic. In the rotation angle of the filaments of the beam, ψ1(x,t) and ψ2(x,t), the dissipation is occasioned by the memory effect. In the transverse vibrations ϕ1(x,t) and ϕ2(x,t) we do not have dissipation and the system is purely elastic. For this type of beam we show the uniform stabilization, i.e., the rate of decay has directly relation with the velocity of the relaxation function.
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    Existence of solutions and optimal control for a model of tissue invasion by solid tumours
    (Journal of Mathematical Analysis and Applications, 2015-01-01) Araujo, Anderson L.A. de; Magalhães, Paulo Marcelo Dias De
    In this paper we study the distributed optimal control problem for the two-dimensional mathematical model of cancer invasion. Existence of optimal state-control and stability is proved and an optimality system is derived.
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    An analysis of a mathematical model describing the geographic spread of dengue disease
    (Journal of Mathematical Analysis and Applications, 2016-12-01) Araujo, Anderson L. A. de; Boldrini, José Luiz; Calsavara, Bianca Morelli Rodolfo
    We consider a system of nonlinear partial differential equations corresponding to a generalization of a mathematical model for geographical spreading of dengue disease proposed in the article by Maidana and Yang (2008) [5]. As in that article, the mosquito population is divided into subpopulations: winged form (mature female mosquitoes) and aquatic form (comprising eggs, larvae and pupae); the human population is divided into the subpopulations: susceptible, infected and removed (or immune). On the other hand, differently from the work by Maidana and Yang, who considered just the one dimensional case with constant coefficients, in the present we allow higher spatial dimensions and also parameters depending on space and time. This last generalization is done to cope with possible abiotic effects as variations in temperature, humidity, wind velocity, carrier capacities, and so on; thus, the results hold for more realistic situations. Moreover, we also consider the effects of additional control terms. We perform a rigorous mathematical analysis and present a result on existence and uniqueness of solutions of the problem; furthermore, we obtain estimates of the solution in terms of certain norms of the given parameters of the problem. This kind of result is important for the analysis of optimal control problems with the given dynamics; to exemplify their utility, we also briefly describe how they can be used to show the existence of optimal controls that minimize a given optimality criteria.
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    Non-Homogeneous Thermoelastic Timoshenko Systems
    (Bulletin of the Brazilian Mathematical Society, New Series, 2017-09) Alves, M. S.; Silva, M. A. Jorge; Ma, T. F.; Rivera, J. E. Muñoz
    The well-established Timoshenko system is characterized by a particular relation between shear stress and bending moment from its constitutive equations. Accordingly, a (thermal) dissipation added on the bending moment produces exponential stability if and only if the so called “equal wave speeds” condition is satisfied. This remarkable property extends to the case of non-homogeneous coefficients. In this paper, we consider a non-homogeneous thermoelastic system with dissipation restricted to the shear stress. To this new problem, by means of a delicate control observability analysis, we prove that a local version of the equal wave speeds condition is sufficient for the exponential stability of the system. Otherwise, we study the polynomial stability of the system with decay rate depending on the regularity of initial data.