We prove uniqueness of the invariant measure and the exponential convergence to equilibrium for a stochastic dissipative system whose drift is perturbed by a bounded function.

Let $S\left(\lambda \right)$ be the scattering matrix related to the wave equation in the exterior of a non-trapping obstacle $𝒪\subset {\mathbf{R}}^n$, $n\ge 3$ with Dirichlet or Neumann boundary conditions on $\partial 𝒪$. The function $s\left(\lambda \right)$, called scattering phase, is determined from the equality $e^{-2\pi is\left(\lambda \right)}=\det S\left(\lambda \right)$. We show that $s\left(\lambda \right)$ has an asymptotic expansion $s\left(\lambda \right)\sim {\sum }_{j=0}^{\infty }{c}_j{\lambda }^{n-j}$ as $\lambda \to +\infty$ and we compute the first three coefficients. Our result proves the conjecture of Majda and Ralston for non-trapping obstacles.

We consider the double-diffusive convection phenomenon and analyze the governing equations. A system of partial differential equations describing the convective flow arising when a layer of fluid with a dissolved solute is heated from below is considered. The problem is placed in a functional analytic setting in order to prove a theorem on existence, uniqueness and continuous dependence on initial data of weak solutions in the class $([0,\infty );H)\cap L{²}_{loc}({ℝ}^{+};V)$. This theorem enables us to show that the infinite-dimensional...

We derive an asymptotic formula of a new type for variational solutions of the Dirichlet problem for elliptic equations of arbitrary order. The only a priori assumption on the coefficients of the principal part of the equation is the smallness of the local oscillation near the point.

In this paper we deal with the problem of asymptotic integration of nonlinear differential equations with $p-$Laplacian, where $1<p<2$. We prove sufficient conditions under which all solutions of an equation from this class are converging to a linear function as $t\to \infty$.

We study the leading order behaviour of positive solutions of the equation $-\Delta u+ϵu-{\left|u\right|}^{p-2}u+{\left|u\right|}^{q-2}u=0,x\in {ℝ}^N$, where $N\ge 3$, $q>p>2$ and when $ϵ>0$ is a small parameter. We give a complete characterization of all possible asymptotic regimes as a function of $p$, $q$ and $N$. The behavior of solutions depends sensitively on whether $p$ is less, equal or bigger than the critical Sobolev exponent $2^{*}=\frac{2N}{N-2}$. For $p<2^{*}$ the solution asymptotically coincides with the solution of the equation in which the last term is absent. For $p>2^{*}$ the solution asymptotically coincides...