We prove comparison results between viscosity sub and supersolutions of degenerate elliptic and parabolic equations associated to, possibly non-linear, Neumann boundary conditions. These results are obtained under more general assumptions on the equation (in particular the dependence in the gradient of the solution) and they allow applications to quasilinear, possibly singular, elliptic or para...

This paper studies the global existence and uniqueness of classical solutions for a generalized quasilinear parabolic equation with appropriate initial and mixed boundary conditions. Under some practicable regularity criteria on diffusion item and nonlinearity, we establish the local existence and uniqueness of classical solutions based on a contraction mapping. This local solution can be conti...

This survey is concerned with positive solutions of nonlinear parabolic equations. Assuming that the underlying domain and the equation have certain reflectional symmetries, the presented results show how positive solutions reflect the symmetries. Depending on the class of solutions considered, the symmetries for all times or asymptotic symmetries are established. Several classes of problems, i...

We propose a new method based on the invariant properties of the ansatz of the Hirota method whcih have been discovered recently. This method allows one to construct new solutions for a certain class the dissipative equations classified by degrees of homogeneity. This algorithm is similar to the method of “dressing” the solutions of integrable equations. A class of new solutions is constructed....

Abstract We consider a Cauchy–Dirichlet problem for quasilinear second order parabolic equation with lower term driven by singular coefficient. establish an existence result to such and we describe the time behavior of solution in case infinite–time horizon.

We formulate a quasilinear parabolic equation describing the behavior of global-in-time solution to semilinear equation. study this in accordance with blow-up and quenching patterns original This is new theory partial differential equations presents several difficulties for mathematical analysis. Two approaches are examined: functional analysis viscosity solution.

We study a two-point free boundary problem in a sector for a quasilinear parabolic equation. The boundary conditions are assumed to be spatially and temporally “self-similar” in a special way. We prove the existence, uniqueness and asymptotic stability of an expanding solution which is selfsimilar at discrete times. We also study the existence and uniqueness of a shrinking solution which is sel...

This work is concerned with positive classical solutions for a quasilinear parabolic equation with a gradient term and nonlinear boundary flux. We find sufficient conditions for the existence of global and blow-up solutions. Moreover, an upper bound for the ‘blow-up time’, an upper estimate of the ‘blow-up rate’ and an upper estimate of the global solution are given. Finally, some application e...