L ∞-Estimates for nonlinear elliptic Neumann boundary value problems

In this paper we prove the L ^∞-boundedness of solutions of the quasilinear elliptic equation

Hölder estimates for solutions to the degenerate boundary-value Venttsel' problem for parabolic and elliptic equations of nondivergence type

The authors continue to study the Venttsel' problem, i.e., the boundary-value problem for a parabolic or elliptic equation with the boundary condition in the form of a parabolic or elliptic equation with respect to tangent variables. A priori estimates for the Hölder norms of solutions are established in the case of quasilinear equations of nondivergence form with a quasilinear degenerate boundary Venttsel' condition. Bibliography: 16 titles.

     

The venttse’ problem for nonlinear elliptic equations

The solvability of the fully nonlinear stationary Venttsel' problem is established. The equation and the boundary condition are assumed to be uniformly elliptic. Bibliography: 12 titles. Translated fromProblemy Matematicheskogo Analiza, No. 19, 1999, pp. 3–26.     

Local Hölder continuity for some doubly nonlinear parabolic equations in measure spaces

We establish the local Hölder continuity for the nonnegative weak solutions of certain doubly nonlinear parabolic equations possessing a singularity in the time derivative part and a degeneracy in the principal part. The proof involves the method of intrinsic scaling and the setting is a measure space equipped with a doubling non-trivial Borel measure supporting a Poincaré inequality.     

Hölder estimates for quasilinear doubly degenerate parabolic equations

For positive bounded generalized solutions of degenerate parabolic equations of the form t 0, m 2, one establishes local Hölder estimates, independent of the lower bounds of the indicated solutions.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akad. Nauk SSSR, Vol. 171, pp. 70–105, 1989.     

Variational inequalities for a system of elliptic–parabolic equations

We create a general framework for mathematical study of variational inequalities for a system of elliptic–parabolic equations. In this paper, we establish a solvability theorem concerning the existence of solutions for the vector-valued elliptic–parabolic variational inequality with time-dependent constraint. Moreover, we give some applications of the system, for example, time-dependent boundary obstacle problem and time-dependent interior obstacle problem.     

Hölder estimate for the solution of degenerate parabolic equations

Consider the degenerate parabolic equations of the type $$u_t = div A(x,t,u,Du) + b(x,t,u,Du)$$ which is of the same nature as $$u_t = div|Du|^p Du + |Du|^{p + 2} (p > 2).$$ This paper is to study the \(C^{1 + \alpha } ,\frac{{1 + \alpha }}{2}\) Hölder continuity of a class of degenerate parabolic equations and the existence and uniqueness of the initial boundary value problem.     

On a Poincaré type formula for solutions of singular and degenerate elliptic equations

We provide a geometric Poincaré type formula for stable solutions of ?Δ _p (u) = f(u). From this, we derive a symmetry result in the plane. This work is a refinement of previous results obtained by the authors under further integrability and regularity assumptions.     

A Galerkin method for mixed parabolic–elliptic partial differential equations

In this article boundary value problems for partial differential equations of mixed elliptic–parabolic type are considered. To ensure that the considered problems possess a unique solution, the usual variational existence proof for parabolic problems is extended to the mixed situation. Further, the convergence of approximations computed by a time-space Galerkin method to the solution of the mixed problem is proven and error estimates are given.     

On Lipschitz solutions for some forward–backward parabolic equations

We investigate the existence and properties of Lipschitz solutions for some forward–backward parabolic equations in all dimensions. Our main approach to existence is motivated by reformulating such equations into partial differential inclusions and relies on a Baire's category method. In this way, the existence of infinitely many Lipschitz solutions to certain initial-boundary value problem of those equations is guaranteed under a pivotal density condition. Under this framework, we study two important cases of forward–backward anisotropic diffusion in which the density condition can be realized and therefore the existence results follow together with micro-oscillatory behavior of solutions. The first case is a generalization of the Perona–Malik model in image processing and the other that of Höllig's model related to the Clausius–Duhem inequality in the second law of thermodynamics.     

Long-term analysis of degenerate parabolic equations in ℝ N

Longtime behavior of degenerate equations with the nonlinearity of polynomial growth of arbitrary order on the whole space R^N is considered. By using -trajectories methods, we proved that weak solutions generated by degenerate equations possess an (L_U² (R^N), L_loc² (R^N))-global attractor. Moreover, the upper bounds of the Kolmogorov ε-entropy for such global attractor are also obtained.