Supersolution

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Vy Khoi Le - One of the best experts on this subject based on the ideXlab platform.

Dragospatru Covei - One of the best experts on this subject based on the ideXlab platform.

Siegfried Carl - One of the best experts on this subject based on the ideXlab platform.

  • Quasilinear parabolic variational inequalities with multi-valued lower-order terms
    Zeitschrift für angewandte Mathematik und Physik, 2014
    Co-Authors: Siegfried Carl, Vy K. Le
    Abstract:

    In this paper, we provide an analytical frame work for the following multi-valued parabolic variational inequality in a cylindrical domain $${Q = \Omega \times (0, \tau)}$$ Q = Ω × ( 0 , τ ) : Find $${{u \in K}}$$ u ∈ K and an $${{\eta \in L^{p'}(Q)}}$$ η ∈ L p ′ ( Q ) such that $$\eta \in f(\cdot,\cdot,u), \quad \langle u_t + Au, v - u\rangle + \int_Q \eta (v - u)\,{\rm d}x{\rm d}t \ge 0, \quad \forall \, v \in K,$$ η ∈ f ( · , · , u ) , 〈 u t + Au , v − u 〉 + ∫ Q η ( v − u ) d x d t ≥ 0 , ∀ v ∈ K , where $${{K \subset X_0 = L^p(0,\tau;W_0^{1,p}(\Omega))}}$$ K ⊂ X 0 = L p ( 0 , τ ; W 0 1 , p ( Ω ) ) is some closed and convex subset, A is a time-dependent quasilinear elliptic operator, and the multi-valued function $${{s \mapsto f(\cdot,\cdot,s)}}$$ s ↦ f ( · , · , s ) is assumed to be upper semicontinuous only, so that Clarke’s generalized gradient is included as a special case. Thus, parabolic variational–hemivariational inequalities are special cases of the problem considered here. The extension of parabolic variational–hemivariational inequalities to the general class of multi-valued problems considered in this paper is not only of disciplinary interest, but is motivated by the need in applications. The main goals are as follows. First, we provide an existence theory for the above-stated problem under coercivity assumptions. Second, in the noncoercive case, we establish an appropriate sub-Supersolution method that allows us to get existence, comparison, and enclosure results. Third, the order structure of the solution set enclosed by sub-Supersolutions is revealed. In particular, it is shown that the solution set within the sector of sub-Supersolutions is a directed set. As an application, a multi-valued parabolic obstacle problem is treated.

  • the sub and Supersolution method for variational hemivariational inequalities
    Nonlinear Analysis-theory Methods & Applications, 2008
    Co-Authors: Siegfried Carl
    Abstract:

    Abstract The well-known method of sub- and Supersolutions is a powerful tool for proving existence and comparison results for initial and/or boundary value problems of nonlinear ordinary differential equations as well as for nonlinear partial differential equations of elliptic and parabolic type. The main goal of this paper is to extend the idea of the sub- and Supersolution method in a natural and systematic way to quasilinear elliptic variational–hemivariational inequalities. Owing to the intrinsic asymmetry of the latter (where the problems are stated as inequalities rather than as equalities) an appropriate generalization of the notion of sub- and Supersolutions to variational–hemivariational inequalities is by no means straightforward. The obtained results of this paper complement the development of the sub- and Supersolution method for nonsmooth variational problems presented in a recent monograph by S. Carl, Vy K. Le and D. Motreanu.

  • The sub- and Supersolution method for variational–hemivariational inequalities
    Nonlinear Analysis-theory Methods & Applications, 2008
    Co-Authors: Siegfried Carl
    Abstract:

    Abstract The well-known method of sub- and Supersolutions is a powerful tool for proving existence and comparison results for initial and/or boundary value problems of nonlinear ordinary differential equations as well as for nonlinear partial differential equations of elliptic and parabolic type. The main goal of this paper is to extend the idea of the sub- and Supersolution method in a natural and systematic way to quasilinear elliptic variational–hemivariational inequalities. Owing to the intrinsic asymmetry of the latter (where the problems are stated as inequalities rather than as equalities) an appropriate generalization of the notion of sub- and Supersolutions to variational–hemivariational inequalities is by no means straightforward. The obtained results of this paper complement the development of the sub- and Supersolution method for nonsmooth variational problems presented in a recent monograph by S. Carl, Vy K. Le and D. Motreanu.

  • Comparison results for a class of quasilinear evolutionary hemivariational inequalities
    2007
    Co-Authors: Siegfried Carl
    Abstract:

    We consider a class of quasilinear evolutionary hemivariational inequalities under nonmonotone multivalued flux boundary conditions. Our main goal is to provide existence and comparison results in terms of appropriately defined sub- and Supersolutions on the basis of which one can prove compactness and extremality results of the solution set within the sector of sub- and Supersolutions.

  • Existence and comparison results for noncoercive and nonmonotone multivalued elliptic problems
    Nonlinear Analysis-theory Methods & Applications, 2006
    Co-Authors: Siegfried Carl
    Abstract:

    Abstract We consider noncoercive quasilinear elliptic inclusions under multivalued flux boundary conditions involving multifunctions of Clarke’s generalized gradient. Our main goal is to provide existence and comparison results which are based on an appropriate generalization of the notions of subsolutions and Supersolutions. Furthermore, compactness and extremality results of the solution set enclosed by an ordered pair of sub–Supersolutions will be proved.

Leandro S Tavares - One of the best experts on this subject based on the ideXlab platform.

Giovany M Figueiredo - One of the best experts on this subject based on the ideXlab platform.