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Autor Díaz Díaz, Jesús Ildefonso |
Documentos disponibles escritos por este autor (214)
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The aim of this paper is to study the asymptotic behavior of the solution of a transmission problem in some chemical reactive flows through periodically perforated domains. The domain is considered to be a fixed bounded open subset ??Rn, in whic[...]![]()
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We study the initial growth of the interfaces of non-negative local solutions of the equation u(t) = (u(m))xx - lambdau(q) when m greater-than-or-equal-to 1 and 0 [...]![]()
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Díaz Díaz, Jesús Ildefonso ; Martin, Sébastien | Elsevier France-editions Scientifiques Medicales Elsevier | 2006-11We consider the Elrod-Adams model extending the classical lubrication Reynolds equation to the case of the possible presence of a cavitation region. We show that the behaviour of the pressure and saturation depends crucially on the behaviour of [...]![]()
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We prove the convergence of the solutions for the incompressible homogeneous magnetohydrodynamics (MHD) system to the solutions to ideal MHD one in the inviscid and non-resistive limit, detailing the explicit convergence rates. For this study we[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Arjona, Alicia ; Fernández, José ; Rundle, J.B. | Birkhäuser | 2008-10-18In the early eighties Rundle (1980, 1981a,b, 1982) developed the techniques needed for calculations of displacements and gravity changes due to internal sources of strain in layered linear elastic-gravitational media. The approximation of the so[...]![]()
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We study the limit case corresponding to a model introduced by G.L. Stenchikov and A. Robock for the evolution of the temperature of an atmospheric column in absence of humidity. The model envolves a degenerate noncoercive quasilinear equation. [...]![]()
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Díaz Díaz, Jesús Ildefonso ; Tello del Castillo, José Ignacio | Amsterdam Elsevier Science 2000 | 2003-03We study a model of growth of tumors with a free boundary delaying the tumor region. We take into account the presence of inhibitors and its interaction with the nutrients. We study the approximate controllability of the internal distribution of[...]![]()
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We analyze the sensitivity of a climatological model with respect to small changes in one of the distinguished parameters: the solar constant. We start by proving the stabilization of solutions of the evolution model when time tends to infinity.[...]![]()
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We present some recent results on the mathematical study of a global two-dimensional stationary climate model. We prove the multiplicity of solutions for some values of a solar parameter. Then, we obtain a S-shaped bifurcation branch.![]()
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We study the flat region of stationary points of the functional integral(Omega) F(|del u(x)|) dx under the constraint u 0 is a given constant. The problem generalizes the classical minimal resistance body problems considered by Newton. We con[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Mingazzini, Tomasso ; Ramos del Olmo, Ángel Manuel | American Institute of Mathematical Sciences | 2012We study an optimal control problem for a semilinear elliptic boundary value problem giving rise to a free boundary. Here, the free boundary is generated due to the fact that the nonlinear term of the state equation is not differentiable. The ne[...]![]()
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We study some retention phenomena on the free boundaries associated to some elliptic and parabolic problems of reaction-diffusion type. This is the case, for instance, of the wait in g time phenomenon for solutions of suitable parabolic equation[...]![]()
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In this comunication we present some results on the uniqueness and existence of BV solutions for the Cauchy-Dirichlet problem associated to the nonlinear diffusion equation b(u)(t) - div(\del u - k(b(u))e\(p-2)(del u - k(b(u))e)) + g(x,u) = f(t,[...]![]()
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We give sufficient conditions, being also necessary in many cases, for the existence of a periodic free boundary generated as the boundary of the support of the periodic solution of a general class of nonlinear parabolic equations. We show some [...]![]()
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We study the uniqueness of solutions of a semilinear elliptic problem obtained from an inverse formulation when the nonlinear terms of the equation are prescribed in a general class of real functions, The inverse problem arises in the modeling o[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Galiano, Gonzalo ; Padial Molina, Juan Francisco | Akademie Verlag GMBH | 1996We obtain the uniqueness of solutions of a nonlocal elliptic problem when the nonlinear terms at the right hand side are assumed to be prescribed. The problem arises in the study of the magnetic confinement of a plasma in a Stellarator device.![]()
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We get some necessary and sufficient conditions for the very weak solvability of the beam equation stated in terms of powers of the distance to the boundary, accordingly to the boundary condition under consideration. We get a L(1)-estimate by us[...]![]()
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Two problems arising in Environment are considered. The first one concerns a conjecture possed by von Neumann in 1955 on the possible modification of the albedo in order to control the Earth surface temperature. The second one is related to the [...]![]()
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We use recent results by Diaz and Rakotoson concerning very weak solutions to linear boundary value problems in order to improve previous work on existence and properties of weak positive solutions to a model example of semilinear singular ellip[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Rakotoson, Jean Michel Theresien | American Institute of Mathematical Sciences | 2010-07We prove the existence of an appropriate function (very weak solution) u in the Lorentz space L(N') (,infinity)(Omega), N' = (N)(N - 1) satisfying Lu - Vu + g (x, u, del u) = mu in Omega an open bounded set of R(N), and u = 0 on partial derivati[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Rakotoson, Jean Michel Theresien ; Schmidt, Paul G. | Real Academia Ciencias Exactas Físicas Y Naturales | 2007We propose a modification of the classical Boussinesq approximation for buoyancy-driven flows of viscous, incompressible fluids in situations where viscous heating cannot be neglected. This modification is motivated by unresolved issues regardin[...]![]()
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We prove a pointwise gradient estimate for the bounded weak solution of the Cauchy problem associated to the quasilinear Fisher-KPP type equation ut ='(u)xx + (u) when ' satisÖes that '(0)=0; and (u) is vanishing only for levels u = 0 and u = 1.[...]![]()
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We present here an improved version of the method introduced by the first author to derive pointwise gradient estimates for the solutions of one-dimensional parabolic problems. After considering a general qualinear equation in divergence form we[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Hernández, Jesús | Department of Mathematics Texas State University | 2014We give a survey of recent results and open problems concerning existence and multiplicity of positive and/or compact support solutions to some semilinear elliptic equations with singular nonlinear terms of absorption type. This includes the cas[...]![]()
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The countable branches of nodal solutions bifurcating from the infinity for a sublinear semilinear equation are described with two different approaches. In the one-dimensional case we use plane phase methods of ordinary differential equations. T[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Fleckinger-Pellé, Jacqueline | American Institute of Mathematical Sciences | 2004We study the positivity, for large time, of the solutions to the heat equation Q(a) (f,u(0)): [GRAPHIC] where Q is a smooth bounded domain in RN and a C R. We obtain some sufficient conditions for having a finite time t(p) > 0 (depending on a a[...]![]()
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In this paper we derive some similarity solutions of a nonlinear equation associated with a free boundary problem arising in the shallow-water approximation in glaciology. In addition we present a classical potential symmetry analysis of this se[...]![]()
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In this paper we consider peculiar kinds of curved slender nearly cylindrical elastic shells enjoying rigidity properties inherited from the geometry which furnish remarkable properties of strength. In two previous papers were addressed the case[...]![]()
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In this paper we consider peculiar kinds of curved slender nearly cylindrical elastic shells enjoying rigidity properties inherited from the geometry which furnish remarkable properties of strength. In two previous papers were addressed the case[...]![]()
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We study the propagation of an initial disturbance u(0)(x) of an equilibrium state s epsilon R for the scalar conservation law u(t) + phi(u)(x) = 0 in (0, + infinity) x R. We give a necessary and sufficient condition on phi for the following pro[...]![]()
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Díaz Díaz, Jesús Ildefonso ; Glowinski, R. ; Guidoboni, G. ; Kim, T. | Real Academia Ciencias Exactas Físicas Y Naturales | 2010We study the transient flow of an isothermal and incompressible Bingham fluid. Similar models arise in completely different contexts as, for instance, in material science, image processing and differential geometry. For the two-dimensional flow [...]![]()
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We extend some previous existence results for quenching type parabolic problems involving a negative power of the unknown in the equation to the case of merely integrable initial data. We show that L1 ? is the suitable framework to obtain the co[...]![]()
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This paper deals with several qualitative properties of solutions of some stationary and parabolic equations associated to the Monge-Ampère operator. Mainly, we focus our attention in the occurrence of a free boundary (separating the region wher[...]![]()
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We study the global and non-global existence of solutions of degenerate singular parabolic equation with sources. In the case of global existence, we prove that any solution must vanish identically after a finite time if either the initial data [...]![]()
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Díaz Díaz, Jesús Ildefonso ; Arcoya Álvarez, David ; Tello del Castillo, José Ignacio | Elsevier | 1998-11-20In this paper we show the existence of a continuous and unbounded connected S-shaped set {(Q, u)} where Q is the solar constant and u satisfies a quasilinear eventually multivalued stationary equation on a Riemannian manifold without boundary ar[...]![]()
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Begout, Pascal ; Díaz Díaz, Jesús Ildefonso | Department of Mathematics Texas State University | 2014“Sharp localized” solutions (i.e. with compact support for each given time t) of a singular nonlinear type Schrödinger equation in the whole space R N are constructed here under the assumption that they have a self-similar structure. It requires[...]![]()
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We prove the compactness of the support of the solution of some stationary Schrödinger equations with a singular nonlinear order term. We present here a sharper version of some energy methods previously used in the literature.![]()
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We prove the compactness of the support of the solution of some stationary Schrödinger equations with a singular nonlinear order term. We present here a sharper version of some energy methods previously used in the literature![]()
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This paper focuses upon the derivation of the similarity solutions of a nonlinear equation associated with a free boundary problem arising in glaciology. We present a potential symmetry analysis of this second order nonlinear degenerate paraboli[...]![]()
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A simple proof of the approximate controllability from the interior for nonlinear evolution problems
The approximate controllability property for solutions of a large class of nonlinear evolution problems is obtained under some abstract conditions which hold, for instance, when the control is the right hand side of the equation. Our very simple[...]![]()
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We study the existence, the asymptotic behaviour near the parabolic boundary and the uniqueness of the solutions of nonlinear reaction-diffusion equations, which blow up on the parabolic boundary. We extend some results for elliptic problems giv[...]![]()
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We prove the existence of a finite extinction time for the solutions of the Dirichlet problem for the total variation flow. For the Neumann problem, we prove that the solutions reach the average of its initial datum in finite time. The asymptoti[...]![]()
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In this survey we collect several results concerning S-type bifurcation curves for the number of solutions of reaction-diffusion stationary equations. In particular, we recall several results in the literature for the case of stationary energy b[...]![]()
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We study the approximate controllability property for y(t) - Delta phi(y) = u chi(omega), on Omega x (0, T), where Omega is a bounded open set of R-N and omega subset of Omega. First, we show some negative results for the case phi(s) = \s\(m-1)s[...]![]()
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Since the beginnings of the 1980s some energy methods have been introduced as an alternative to comparison principles in order to prove space and time localization of solutions of suitable nonlinear parabolic or elliptic equations. The study of [...]![]()
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A degenerate parabolic system consisting in two continuity equations for densities of charged particles and in the Poisson equation for an electric potential is considered. We show the finite speed of propagation, a waiting time property for the[...]![]()
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In this paper we consider the problem determined by the anti-plane shear dynamic deformations for the linear theory of viscoelasticity. First, we prove existence of solutions of the problem determined in a semi-infinite strip. Then, we show that[...]![]()
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The author studies the finite extinction time phenomenon in nonlinear evolution systems with dynamic boundary conditions and of Coulomb friction type problems. He gives some general results and methods and shows that this phenomenon is not a uni[...]