Darcy's law in anisothermic porous medium.
We classify the global behavior of weak solutions of the Keller-Segel system of degenerate and nondegenerate type. For the stronger degeneracy, the weak solution exists globally in time and has a uniform time decay under some extra conditions. If the degeneracy is weaker, the solution exhibits a finite time blow up if the data is nonnegative. The situation is very similar to the semilinear case. Some additional discussion is also presented.
We consider an initial boundary value problem for the equation . We first prove local and global existence results under suitable conditions on f and g. Then we show that weak solutions decay either algebraically or exponentially depending on the rate of growth of g. This result improves and includes earlier decay results established by the authors.
In this paper we study the asymptotic behavior of solutions to the damped, nonlinear vibration equation with self-interaction which is known as degenerate if , and non-degenerate if . We would like to point out that, to the author’s knowledge, exponential decay for this type of equations has been studied just for the special cases of . Our aim is to extend the validity of previous results in [5] to both to the degenerate and non-degenerate cases of . We extend our results to equations with...
We study the decay of solutions to the wave equation in the exterior of several strictly convex bodies. A sufficient condition for exponential decay of the local energy is expressed in terms of the period and the Poincare map of periodic rays in the exterior domain.