6.1 Bounds for Difference Between Two ``Jensen's Gaps'' for N -quasiconvex Functions6.2 Jensen Gap and Taylor Power Series; References; Criteria for Convergence of Iterates in a Compression-Expansion Fixed Point Theorem of Functional Type; 1 Introduction; 2 Preliminaries; 3 Application; References; On Lagrangian Duality in Infinite Dimension and Its Applications; 1 Introduction; 2 Lagrangian Duality in a Classical Framework; 3 A Characterization of Strong Duality in Infinite Dimension; 4 Application to Generalized Nash Equilibrium Problems in Infinite Dimensional Spaces

4.1 The Setting of the Game4.2 Lagrange Multipliers Rule; 4.3 The Role of Assumption S; 5 Conclusion and Further Research Directions; Appendix; References; Stability Analysis of the Inverse Problem of Parameter Identification in Mixed Variational Problems; 1 Introduction; 2 Problem Formulation and Preliminary Results; 3 Optimization Formulations; 4 Asymptotic Stability of the MOLS Approach; 5 Local Stability Estimates; 5.1 Stability of the Output Least-Squares Approach; 5.2 Stability of the Modified Output Least-Squares Approach; 5.3 Stability of the Energy Output Least-Squares Approach

2 Applications to the General Financial Equilibrium Problem2.1 Presentation of the Model; 2.2 The Duality for the Financial Equilibrium Problem; 2.3 The Viewpoints of the Sector and of the System; 2.4 The Contagion Problem; 2.5 An Example of a Markowitz-Type Risk Measure; 3 Applications to the Elastic-Plastic Torsion Problem; 3.1 Presentation of the Problem; 3.2 The Elastic-Plastic Torsion Problem for Linear Operators; 3.3 The Elastic-Plastic Torsion Problem for Nonlinear Monotone Operators; 3.4 Von Mises Functions; 3.5 Radial Solutions; References