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On radially symmetric solutions of some chemotaxis system

Robert Stańczy (2009)

Banach Center Publications

This paper contains some results concerning self-similar radial solutions for some system of chemotaxis. This kind of solutions describe asymptotic profiles of arbitrary solutions with small mass. Our approach is based on a fixed point analysis for an appropriate integral operator acting on a suitably defined convex subset of some cone in the space of bounded and continuous functions.

On solutions of a perturbed fast diffusion equation

Ján Filo (1987)

Aplikace matematiky

The paper concerns the (local and global) existence, nonexistence, uniqueness and some properties of nonnegative solutions of a nonlinear density dependent diffusion equation with homogeneous Dirichlet boundary conditions.

On some nonlocal systems containing a parabolic PDE and a first order ODE

Ádám Besenyei (2010)

Mathematica Bohemica

Two models of reaction-diffusion are presented: a non-Fickian diffusion model described by a system of a parabolic PDE and a first order ODE, further, porosity-mineralogy changes in porous medium which is modelled by a system consisting of an ODE, a parabolic and an elliptic equation. Existence of weak solutions is shown by the Schauder fixed point theorem combined with the theory of monotone type operators.

On some parabolic-elliptic system with self-similar pressure term

Robert Stańczy (2006)

Banach Center Publications

A priori estimates for solutions of a system describing the interaction of gravitationally attracting particles with a self-similar pressure term are proved. The presented theory covers the case of the model with diffusions that obey either Fermi-Dirac statistics or a polytropic one.

On the Convergence of the Approximate Free Boundary for the Parabolic Obstacle Problem

Paola Pietra, Claudio Verdi (1985)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Si discretizza il problema dell'ostacolo parabolico con differenze all'indietro nel tempo ed elementi finiti lineari nello spazio e si dimostrano stime dell'errore per la frontiera libera discreta.

On the eigenfunction expansion method for semilinear dissipative equations in bounded domains and the Kuramoto-Sivashinsky equation in a ball

V. V. Varlamov (2001)

Studia Mathematica

Presented herein is a method of constructing solutions of semilinear dissipative evolution equations in bounded domains. For small initial data this approach permits one to represent the solution in the form of an eigenfunction expansion series and to calculate the higher-order long-time asymptotics. It is applied to the spatially 3D Kuramoto-Sivashinsky equation in the unit ball B in the linearly stable case. A global-in-time mild solution is constructed in the space C ( [ 0 , ) , H s ( B ) ) , s < 2, and the uniqueness...

On the solution of the heat equation with nonlinear unbounded memory

Alexander Doktor (1985)

Aplikace matematiky

The paper deals with the question of global solution u , τ to boundary value problem for the system of semilinear heat equation for u and complementary nonlinear differential equation for τ (“thermal memory”). Uniqueness of the solution is shown and the method of successive approximations is used for the proof of existence of a global solution provided the condition ( 𝒫 ) holds. The condition ( 𝒫 ) is verified for some particular cases (e. g.: bounded nonlinearity, homogeneous Neumann problem (even for unbounded...

On the stability of solutions of nonlinear parabolic differential-functional equations

Stanisław Brzychczy (1996)

Annales Polonici Mathematici

We consider a nonlinear differential-functional parabolic boundary initial value problem (1) ⎧A z + f(x,z(t,x),z(t,·)) - ∂z/∂t = 0 for t > 0, x ∈ G, ⎨z(t,x) = h(x)     for t > 0, x ∈ ∂G, ⎩z(0,x) = φ₀(x)     for x ∈ G, and the associated elliptic boundary value problem with Dirichlet condition (2) ⎧Az + f(x,z(x),z(·)) = 0  for x ∈ G, ⎨z(x) = h(x)    for x ∈ ∂G ⎩ where x = ( x , . . . , x m ) G m , G is an open and bounded domain with C 2 + α (0 < α ≤ 1) boundary, the operator     Az := ∑j,k=1m ajk(x) (∂²z/(∂xj ∂xk)) is...

Currently displaying 261 – 280 of 453