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In this paper, we introduce and investigate mixed vector equilibrium-like problems (MVEPs) on Hadamard manifolds. Specifically, our aim is to establish error bounds for MVEPs. For this, we propose some regularized gap functions for MVEPs under suitable conditions. Then some error bounds for MVEPs in terms of regularized gap functions are obtained with the hypotheses imposed on the data of MVEPs. Our results in this paper are new and can be considered as a significant generalization of some previously known results in the literature. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a new relaxed inertial Tseng extragradient method with self-adaptive step size for approximating common solutions of monotone variational inequality and fixed point problems of quasi-pseudo-contraction mappings in real Hilbert spaces. We prove a strong convergence result for the proposed algorithm without the knowledge of the Lipschitz constant of the cost operator. Moreover, we apply our results to approximate solution of convex minimization problem, and we present some numerical experiments to show the efficiency and applicability of our method in comparison with some existing methods in the literature. Our proposed method is easy to implement. It requires only one projection onto a constructible half-space. [ABSTRACT FROM AUTHOR]

Some properties of solutions of convex sweeping processes with velocity constraints are studied in this paper. Namely, the solution stability with respect to the initial value, the boundedness, the closedness, and the convexity of the solution set are discussed in detail. In addition, an outer estimate for the solution set is given here for the first time and two open questions are raised for further research. Our investigations complement the preceding ones on the solution existence and the solution uniqueness of convex sweeping processes with velocity constraints. [ABSTRACT FROM AUTHOR]

The goal of this paper is to introduce a new class of parametric elliptical variational-hemivariational inequality problems together with parametric inverse problems. We show the existence of solution for parametric inverse problem and well-posedness of parametric elliptical variational-hemivariationl inequality problems. An implementation in nonlinear elasticity, we address the parametric inverse problem for a parametric frictional unilateral contact problem. [ABSTRACT FROM AUTHOR]

Recently, in [Tang GJ, Cen JX, Nguyen VT, et al. Differential variational-hemivariational inequalities: existence, uniqueness, stability, and convergence. J Fixed Point Appl. 2020; DOI: ],we studied a comprehensive system called differential variational-hemivar-iational inequality (DVHVI, for short) which is composed of a nonlinear evolution equation and a time-dependent variational-hemivariational inequality in Banach spaces. We have proved the existence, uniqueness, and stability of the solution in mild sense, as well as a surprising convergence result for DVHVI. However, to illustrate the applicability of those theoretical results in Tang et al., the present paper is devoted to explore a coupled dynamic system which is formulated by a nonlinear reaction–diffusion equation described by a time-dependent nonsmooth semipermeability problem. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the topological structure of solution sets of monotone vector variational inequalities (VVIs). We show that if the weak Pareto solution set of a monotone VVI is disconnected, then each connected component of the set is unbounded. Similarly, this property holds for the proper Pareto solution set. Two open questions on the topological structure of the solution sets of (symmetric) monotone VVIs are raised at the end of the paper. [ABSTRACT FROM AUTHOR]

This paper is concerned with maximization and minimization problems related to a boundary value problem involving a p-Laplacian type operator. These optimization problems are formulated relative to the rearrangement of a fixed function. Firstly, by introducing a truncated function, we establish the existence and uniqueness of the solution of the boundary value problem involving a p-Laplacian type operator, and then, we show that both optimization problems are solvable under some suitable assumptions. Furthermore, we show that the solution of the minimization problem is unique and has some symmetric property if the domain considered is a ball. [ABSTRACT FROM AUTHOR]

In this paper, we construct an iterative algorithm for solving a multitime-type variational inequality problem and prove its convergence. Moreover, we study the weak sharp solutions for the multitime-type variational inequality problem and investigate the finite termination property of the constructed iterative algorithm. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate a class of differential variational inequalities involving a constraint set in Banach spaces. A well-posedness result for the inequality is obtained, including the existence, uniqueness, and stability of the solution in mild sense. Further, we introduce a penalized problem without constraints and prove that the solution to the original inequality can be approached, as a parameter converges to zero, by the solution of the penalized problem. Finally, an application to a comprehensive obstacle parabolic-elliptic system delineates the abstract results. [ABSTRACT FROM AUTHOR]

In this paper, we revisit the numerical solution of the scalar second-order wave equation by discontinuous Galerkin methods. The numerical methods are different from the ones found in existing literature. Moreover, we provide a stability analysis and derive optimal order error estimates through a more direct approach. The error estimate in an H 1 (Ω) -like norm is derived based on an analysis of the truncation error while that in the L 2 (Ω) norm based on an application of the Aubin-Nitsche technique. Numerical simulation results are reported in support of the theoretical error estimates. [ABSTRACT FROM AUTHOR]

In this paper, we study a differential hemivariational inequality (DHVI, for short) in the framework of reflexive Banach spaces. Our aim is three fold. The first one is to investigate the existence and the uniqueness of mild solution, by applying a general fixed-point principle. The second one is to study its exponential stability, by employing the formula for the variation of parameters and inequality techniques. Finally, the third aim is to illustrate an application of our abstract results in the study of an initial and boundary value problem which describes the contact of an elastic rod with an obstacle. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with the existence, multiplicity and concentration of positive solutions for the semilinear Schrödinger-Poisson system − ε 2 Δ u + a (x) u + λ φ (x) u = b (x) f (u) + c (x) | u | 4 u , x ∈ R 3 , − ε 2 Δ φ = u 2 , u ∈ H 1 (R 3) , x ∈ R 3 , where ε > 0 (small) and λ are real parameters, a,b and c are continuous functions, and f is a continuous superlinear and subcritical nonlinearity. First, we prove that there are two families of semiclassical positive solutions for ε > 0 small. Then we show that these solutions are concentrating on some sets which is generated by the minimal points of a and maximal points of b and c. In addition, we investigate the relation between the number of positive solutions and the topology of the set of the global minima(or maxima) of the potentials by minimax theorems and the Ljusternik-Schnirelmann theory. Finally, we obtain some sufficient conditions for the nonexistence of positive ground state solutions. [ABSTRACT FROM AUTHOR]

The paper investigates inverse problems for a class of nonlinear elliptic variational-hemivariational inequalities. We prove results on the well posedness of a variational-hemivariational inequality and on the existence of solution to inverse problems. We illustrate our findings by an inverse problem for a frictional unilateral contact problem in nonlinear elasticity. [ABSTRACT FROM AUTHOR]

One important task in image segmentation is to find a region of interest, which is, in general, a solution of a nonlinear and nonconvex problem. The authors of Chan and Esedoglu (Aspects of total variation regularized L 1 function approximation. SIAM J. Appl. Math. 2005;65:1817–1837) proposed a convex T V − L 1 problem for finding such a region Σ and proved that when a binary input f is given, a solution u ∗ to the convex problem gives rise to other solutions 1 { u ∗ ≥ μ } for a.e. μ ∈ (0 , 1) from which they raised a question of whether or not u ∗ must be binary. The same is to ask if the two-phase Mumford–Shah model in image processing has a unique solution with a binary input. In this paper, we will discuss how to construct a non-binary solution that provides a negative answer to the question through a connection of two ideas, one from the two-phase Mumford–Shah model in image segmentation and the other from mean curvature motions discussed in some geometric problems (e.g. Alter, Caselles, Chambolle. A characterization of convex calibrable sets in R N . Math. Ann. 2005;322:329–366; Chambolle. An algorithm for mean curvature motion. Interfaces Free Boundaries 2004;6:195–218) revealing the nature of non-uniqueness in image segmentation. [ABSTRACT FROM AUTHOR]

This paper represents a continuation of our previous work, where a mathematical model which describes the equilibrium of an elastic body in frictional contact with a moving foundation was considered. An existence and uniqueness result was proved, together with a convergence result. The proofs were carried out by using arguments of elliptic variational inequalities. In this current paper, we complete our model by taking into account the wear of the foundation. This makes the problem evolutionary and leads to a new and nonstandard mathematical model, which couples a time-dependent variational inequality with an integral equation. We provide the unique weak solvability of the model by using a fixed point argument, among others. Then, we penalize the unilateral contact condition and prove that the penalized problem has a unique solution which converges to the solution of the original problem, as the penalization parameter converges to zero. [ABSTRACT FROM AUTHOR]

In this paper, we consider a new class of fully history-dependent quasivariational inequalities which arise in the study of quasistatic models of contact and involve two history-dependent operators. By using a fixed-point theorem and arguments of monotonicity and convexity, we prove an existence and uniqueness result of the solution, which includes as special cases some results already obtained in some papers. Then, the obtained result is applied to two problems of quasistatic frictional contact for viscoelastic materials and the unique weak solvability of each contact problem is obtained. [ABSTRACT FROM AUTHOR]

In this paper, we study the existence of solutions for noncoercive mixed equilibrium problems which are described by the sum of a maximal monotone bifunction and a pseudomonotone (or quasimonotone) bifunction in the sense of Brézis. Our approach is based on recession analysis and on recent results established by the authors for the existence of solutions of mixed equilibrium problems under pseudomonotone perturbations. As an application, we study the existence of solutions for nonlinear evolution equations associated with a noncoercive time-dependent pseudomonotone (or quasimonotone) operator. [ABSTRACT FROM AUTHOR]

In the last decade, more and more authors have attempted to treat in a unified manner, by means of some binary or ternary relations, various equilibrium or quasi-equilibrium problems encountered in literature. Several types of variational relation problems have been investigated in many recent papers in which, as for other mathematical models, the main focus has been on sufficient conditions for the existence of solution. The existence of solution has been also studied for several types of systems of two variational relation problems called either mixed variational relation problems or simultaneous variational relation problems. In this paper, we deal with the existence of solutions for two types of mixed variational relation problems in which the involved relations (one binary and the other ternary) are linked by a certain condition of compatibility. [ABSTRACT FROM AUTHOR]

In this paper, we consider a general class of history-dependent quasivariational inequalities with constraints. Our aim is to study the behavior of the solution with respect to the set of constraints and, in this matter, we prove a continuous dependence result. The proof is based on various estimates and monotonicity arguments. Then, we consider two mathematical models which describe the equilibrium of a viscoplastic and viscoelastic body, respectively, in contact with a deformable foundation. The variational formulation of each model is in a form of a history-dependent quasivariational inequality for the displacement field, governed by a set of constraints. We prove the unique weak solvability of each model, then we use our abstract result to prove the continuous dependence of the solution with respect to the set of constraints. [ABSTRACT FROM AUTHOR]

In this paper, we introduce and study the generalized-D-gap function for an equilibrium problem. We give sufficient conditions under which a critical point of the generalized-D-gap function is a solution of the equilibrium problem, and develop a descent scheme for locating these critical points. Using the generalized-D-gap function, we construct an error bound for the equilibrium problem. We support our approach with concrete examples. [ABSTRACT FROM AUTHOR]

This paper points out some fatal errors in the equivalent formulations used in Noor 2011 [Noor MA. Projection iterative methods for solving some systems of general nonconvex variational inequalities. Applied Analysis. 2011;90:777–786] and consequently in Noor 2009 [Noor MA. System of nonconvex variational inequalities. Journal of Advanced Research Optimization. 2009;1:1–10], Noor 2010 [Noor MA, Noor KI. New system of general nonconvex variational inequalities. Applied Mathematics E-Notes. 2010;10:76–85] and Wen 2010 [Wen DJ. Projection methods for a generalized system of nonconvex variational inequalities with different nonlinear operators. Nonlinear Analysis. 2010;73:2292–2297]. Since these equivalent formulations are the main tools to suggest iterative algorithms and to establish the convergence results, the algorithms and results in the aforementioned articles are not valid. It is shown by given some examples. To overcome with the problems in these papers, we consider a new system of extended regularized nonconvex variational inequalities, and establish the existence and uniqueness result for a solution of the aforesaid system. We suggest and analyse a new projection iterative algorithm to compute the unique solution of the system of extended regularized nonconvex variational inequalities which is also a fixed point of a nearly uniformly Lipschitzian mapping. Furthermore, the convergence analysis of the proposed iterative algorithm under some suitable conditions is studied. As a consequence, we point out that one can derive the correct version of the algorithms and results presented in the above mentioned papers. [ABSTRACT FROM AUTHOR]

In this paper, we consider evolution equations with time-dependent pseudomonotone and quasimonotone operators by a new approach based on equilibrium problems theory. We establish new existence results for equilibrium problems associated to pseudomonotone and quasimonotone bifunctions in the topological sense. The results obtained are then applied to derive existence of solutions for evolution equations. The approach is new and leads to improve and unify most of the results obtained in this direction. [ABSTRACT FROM AUTHOR]

In this paper, we present a globally convergent algorithm for the computation of a minimizer of the Tikhonov functional with sparsity promoting penalty term for nonlinear forward operators in Banach space. Thedual TIGRAmethod uses a gradient descent iteration in the dual space at decreasing values of the regularization parameter, where the approximation obtained withserves as the starting value for the dual iteration with parameter. With the discrepancy principle as a global stopping rule, the method further yields an automatic parameter choice. We prove convergence of the algorithm under suitable step-size selection and stopping rules and illustrate our theoretic results with numerical experiments for the nonlinear autoconvolution problem. [ABSTRACT FROM PUBLISHER]

In the present paper, we study Newton’s method for variational inequality problems. Under the-condition, the generalized-theory and-theory for Newton’s method are established. As an application, Smale’s point estimate theory for analytic mappings are given. [ABSTRACT FROM PUBLISHER]

This paper deals with some problems of calculus of variation for functionals with deviating arguments. We use the direct method to establish some existence results and extend the corresponding results obtained in literature. [ABSTRACT FROM AUTHOR]

In this paper, a vector network equilibrium problem with capacity constraints of arcs is studied. By virtue of Fan-Browder’ fixed point theorem, an existence result of a (weak) vector equilibrium flow is derived. By using nonlinear scalarization methods, some sufficient and necessary conditions for a weak vector equilibrium flow are obtained. [ABSTRACT FROM AUTHOR]

In this paper, a class of generalized evolution variational inequalities arising in quasistatic friction contact problem for viscoelastic materials is introduced and studied. Under some suitable assumptions, we obtain an existence and uniqueness theorem of the solution for the generalized evolution variational inequalities by using Banach’s fixed point theorem. Moreover, we study two numerical approximation schemes of the problem: semidiscrete scheme and fully discrete scheme. For both schemes, we prove the existence of the solution and derive the error estimations. [ABSTRACT FROM AUTHOR]