The Dirichlet-to-Neumann operator associated with the $1$-Laplace operator and evolution problems

TL;DR

This paper studies the Dirichlet-to-Neumann operator linked to the 1-Laplace operator in L^1, establishing its mathematical properties and applying it to evolution problems, including stability and well-posedness results.

Contribution

It introduces a novel realization of the Dirichlet-to-Neumann operator for the 1-Laplace operator as a sub-differential in L^1, and applies it to evolution problems with new stability and well-posedness results.

Findings

The Dirichlet-to-Neumann operator can be realized as a sub-differential in L^1.

Stability/compactness results for boundary data in L^1.

Well-posedness and long-time stability of evolution problems governed by this operator.

Abstract

We present first results on the Dirichlet-to-Neumann operator associated with the $1$-Laplace operator in $L^1$. In particular, we show that this operator can be realized as a sub-differential operator in $L^1\times L^{\infty}$ of a homogeneous convex, continuous functional with effective domain $L^1$. Even though the Dirichlet problem associated with the $1$-Laplace operator loses the property that weak solutions for boundary data in $L^1$ are unique, we prove a type of stability/compactness result with respect to the boundary data in $L^1$ of this problem. We apply our results for the stationary Dirichlet problem to evolution problems governed by the Dirichlet-to-Neumann operator, which can equivalently be formulated as singular coupled elliptic-parabolic initial boundary-value problems. For initial data in $L^q$, $1\le q\le \infty$, we obtain well-posedness, that every mild solution is, indeed, a strong solution, and establish long-time stability of the semigroup generated by the negative Dirichlet-to-Neumann operator associated with the $1$-Laplace operator.