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Some new results on a Stefan problem in a concentrated capacity

Enrico Magenes (1992)

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

An existence and uniqueness theorem for a nonlinear parabolic system of partial differential equations, connected with the theory of heat conduction with a transition phase in a concentrated capacity, is given in sufficiently general hypotheses on the data.

Some new results related to the null controllability of the 1 - d heat equation

Antonio López, Enrique Zuazua (1997/1998)

Séminaire Équations aux dérivées partielles

We address three null controllability problems related to the 1 - d heat equation. First we show that the 1 - d heat equation with a rapidly oscillating density is uniformly null controllable as the period of the density tends to zero. We also prove that the same result holds for the finite-difference semi-discretization in space of the constant coefficient heat equation as the step size tends to zero. Finally, we prove that the null controllability of the constant coefficient heat equation can be obtained...

Some orthogonal decompositions of Sobolev spaces and applications

H. Begehr, Yu. Dubinskiĭ (2001)

Colloquium Mathematicae

Two kinds of orthogonal decompositions of the Sobolev space W̊₂¹ and hence also of W - 1 for bounded domains are given. They originate from a decomposition of W̊₂¹ into the orthogonal sum of the subspace of the Δ k -solenoidal functions, k ≥ 1, and its explicitly given orthogonal complement. This decomposition is developed in the real as well as in the complex case. For the solenoidal subspace (k = 0) the decomposition appears in a little different form. In the second kind decomposition the Δ k -solenoidal...

Some partial differential equations in Clifford analysis

Elena Obolashvili (1996)

Banach Center Publications

Using Clifford analysis in a multidimensional space some elliptic, hyperbolic and parabolic systems of partial differential equations are constructed, which are related to the well-known classical equations. To obtain parabolic systems Clifford algebra is modified and some corresponding differential operator is constructed. For systems obtained the boundary and initial value problems are solved.

Some possibly degenerate elliptic problems with measure data and non linearity on the boundary

Thierry Gallouët, Yannick Sire (2011)

Annales de la faculté des sciences de Toulouse Mathématiques

The goal of this paper is to study some possibly degenerate elliptic equation in a bounded domain with a nonlinear boundary condition involving measure data. We investigate two types of problems: the first one deals with the laplacian in a bounded domain with measure supported on the domain and on the boundary. A second one deals with the same type of data but involves a degenerate weight in the equation. In both cases, the nonlinearity under consideration lies on the boundary. For the first problem,...

Some problems of parabolic type with discontinuous nonlinearities on convex constraints

Marlène Frigon, Antonio Marino, Claudio Saccon (1990)

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

We study semilinear equations and inequalities of parabolic type with discontinuous nonlinearities, possibly subjected to convex or even nonconvex constraint conditions. To prove some existence theorems we regard the solutions as «curves of maximal relaxed slope» for a suitable functional on the given constraint.

Currently displaying 741 – 760 of 1688