Stability of some constraint systems and optimization problems

VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY INSTITUTE OF MATHEMATICS DUONG THI KIM HUYEN STABILITY OF SOME CONSTRAINT SYSTEMS AND OPTIMIZATION PROBLEMS DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN MATHEMATICS HANOI - 2019 VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY INSTITUTE OF MATHEMATICS DUONG THI KIM HUYEN STABILITY OF SOME CONSTRAINT SYSTEMS AND OPTIMIZATION PROBLEMS Speciality: Applied Mathematics Speciality code: 46 01 12 DISSERTATION FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN MATHEMATICS Supervisor: Prof Dr.Sc NGUYEN DONG YEN HANOI - 2019 Confirmation This dissertation was written on the basis of my research works carried out at the Institute of Mathematics, Vietnam Academy of Science and Technology, under the guidance of Prof Nguyen Dong Yen All results presented in this dissertation have never been published by others Hanoi, October 2, 2019 The author Duong Thi Kim Huyen i Acknowledgment I still remember very well the first time I have met Prof Nguyen Dong Yen at Institute of Mathematics On that day I attended a seminar of Prof Hoang Tuy about Global Optimization At the end of the seminar, I came to talk with Prof Nguyen Dong Yen I said to him that I wanted to learn about Optimization Theory, and I asked him to let me be his student He did say yes A few days later, he sent me an email and he informed me that my master thesis would be about “openness of set-valued maps and implicit multifunction theorems” Three years later, I defensed successfully my master thesis under his guidance at Institute of Mathematics, Vietnam Academy of Science and Technology I would say I am deeply indebted to him not only for his supervision, encouragement and support in my research, but also for his precious advices in life The Institute of Mathematics is a wonderful place for studying and working I would like to thank all the staff members of the Institute who have helped me to complete my master thesis and this work within the schedules I also would like to express my special appreciation to Prof Hoang Xuan Phu, Assoc Prof Ta Duy Phuong, Assoc Prof Phan Thanh An, and other members of the weekly seminar at Department of Numerical Analysis and Scientific Computing, Institute of Mathematics, as well as all the members of Prof Nguyen Dong Yen’s research group for their valuable comments and suggestions on my research results I greatly appreciate Dr Pham Duy Khanh and Dr Nguyen Thanh Qui, who have helped me in typing my master thesis when I was pregnant with my first baby, and encouraged me to pursue a PhD program I would like to thank Prof Le Dung Muu, Prof Nguyen Xuan Tan, Assoc Prof Truong Xuan Duc Ha, Assoc Prof Nguyen Nang Tam, Assoc Prof Nguyen Thi Thu Thuy, and Dr Le Hai Yen, for their careful ii readings of the first version of this dissertation and valuable comments Financial supports from the Vietnam National Foundation for Science and Technology Development (NAFOSTED) are gratefully acknowledged I am sincerely grateful to Prof Jen-Chih Yao from Department of Applied Mathematics, National Sun Yat-sen University, Taiwan, and Prof ChingFeng Wen from Research Center for Nonlinear Analysis and Optimization, Kaohsiung Medical University, Taiwan, for granting several short-termed scholarships for my doctorate studies I would like to thank Prof Xiao-qi Yang for his supervision during my stay at Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, by the Research Student Attachment Program I would like to show my appreciation to Prof Boris Mordukhovich from Department of Mathematics, Wayne State University, USA, and Ass Prof Tran Thai An Nghia from Department of Mathematics and Statistics, Oakland University, USA, for valuable comments and encouragement on my research works My enormous gratitude goes to my husband and my son for their love, encouragement, and especially for their patience during the time I was working intensively to complete my PhD studies Finally, I would like to express my love and thanks to my parents, my parents in law, my ant in law, and all my sisters and brothers for their strong encouragement and support iii Contents Table of Notation vi Introduction viii Chapter Preliminaries 1.1 Basic Concepts from Variational Analysis 1.2 Properties of Multifunctions and Implicit Multifunctions 1.3 An Overview on Implicit Function Theorems for Multifunctions Chapter Linear Constraint Systems under Total Perturbations 2.1 An Introduction to Parametric Linear Constraint Systems 2.2 The Solution Maps of Parametric Linear Constraint Systems 11 2.3 Stability Properties of Generalized Linear Inequality Systems 19 2.4 The Solution Maps of Linear Complementarity Problems 21 2.5 The Solution Maps of Affine Variational Inequalities 27 2.6 Conclusions 33 Chapter Linear Constraint Systems under Linear Perturbations 35 3.1 3.2 3.3 Stability properties of Linear Constraint Systems under Linear Perturbations 36 Solution Stability of Linear Complementarity Problems under Linear Perturbations 38 Solution Stability of Affine Variational Inequalities under Linear Perturbations 48 iv 3.4 Conclusions 57 Chapter Sensitivity Analysis of a Stationary Point Set Map under Total Perturbations 59 4.1 Problem Formulation 60 4.2 Auxiliary Results 61 4.3 Lipschitzian Stability of the Stationary Point Set Map 64 4.3.1 Interior Points 64 4.3.2 Boundary Points 70 4.4 The Robinson Stability of the Stationary Point Set Map 80 4.5 Applications to Quadratic Programming 84 4.6 Results Obtained by Another Approach 92 4.7 Proof of Lemma 4.3 96 4.8 Proof of Lemma 4.4 97 4.9 Conclusions 100 General Conclusions 101 List of Author’s Related Papers 102 References 103 Index 110 v Table of Notations R ¯ R ∅ Rn x, y ||x|| B(x, ρ) ¯ ρ) B(x, BX N (¯ x) Rn+ Rn− Rm×n detA AT ker A E rank C C X∗ X ∗∗ A∗ : Y ∗ → X ∗ d(x, Ω) N (¯ x; Ω) or NΩ (¯ x) N (¯ x; Ω) or NΩ (¯ x) Ω x −→ x¯ the set of real numbers the set of extended real numbers the empty set the n-dimensional Euclidean vector space the scalar product in an Euclidean space the norm of a vector x the open ball centered x with radius ρ the closed ball centered x with radius ρ the open unit ball of X the family of the neighborhoods of x¯ the nonnegative orthant in Rn the nonpositive orthant in Rn the vector space of m × n real matrices the determinant of matrix A the transpose of matrix A the kernel of matrix A (i.e., the null space of the operator corresponding to matrix A) the unit matrix the rank of matrix C a negative semidefinite matrix the dual space of a Banach space X the dual space of X ∗ the adjoint operator of a bounded linear operator A : X → Y the distance from x to a set Ω the Fr´echet normal cone of Ω at x¯ the Mordukhovich normal cone of Ω at x¯ x → x¯ and x ∈ Ω vi Limsup ∇f (¯ x) ∇2 f (¯ x) ∇x ψ(¯ x, y¯) epif ∂f (x) ∂ ∞ f (x) ∂ f (¯ x, y¯) ∂x ψ(¯ x, y¯) g◦f F :X⇒Y gph F D∗ F (¯ x, y¯)(·) D∗ F (¯ x, y¯)(·) int D L⊥ L∗ cone D resp diag[Mαα , Mββ , Mγγ ] LCP AVI TRS MFCQ the Painlev´e-Kuratowski upper limit the Fr´echet derivative of f : X → Y at x¯ the Hessian matrix of f : X → R at x¯ the partial derivative of ψ : X × Y → Z in x at (¯ x, y¯) the epigraph of a function f : X → R the Mordukhovich subdifferential of f at x the singular subdifferential of f at x the second-order subdifferential of f at x¯ in direction y¯ ∈ ∂f (¯ x) the partial subdifferential of ψ : X × Y → R in x at (¯ x, y¯) the composite function of g and f a set-valued map between X and Y the graph of F the Fr´echet coderivative of F at (¯ x, y¯) the Mordukhovich coderivative of F at (¯ x, y¯) the topological interior of D the orthogonal complement of a set L the polar cone of L the cone generated by D respectively a block diagonal matrix linear complementarity problem affine variational inequality the trust-region subproblem The Mangasarian-Fromovitz Constraint Qualification vii Introduction Many real problems lead to formulating equations and solving them These equations may contain parameters like initial data or control variables The solution set of a parametric equation can be considered as a multifunction (that is, a point-to-set function) of the parameters involved The latter can be called an implicit multifunction A natural question is that “What properties can the implicit multifunction possess?” Under suitable differentiability assumptions, classical implicit function theorems have addressed thoroughly the above question from finite-dimensional settings to infinite-dimensional settings Nowadays, the models of interest (for instance, constrained optimization problems) outrun equations Thus, Variational Analysis (see, e.g., [50, 80]) has appeared to meet the need of this increasingly strong development J.-P Aubin, J.M Borwein, A.L Dontchev, B.S Mordukhovich, H.V Ngai, S.M Robinson, R.T Rockafellar, M Th´era, Q.J Zhu, and other authors, have studied implicit multifunctions and qualitative aspects of optimization and equilibrium problems by different approaches In particular, with the two-volume book “Variational Analysis and Generalized Differentiation” (see [50, 51]) and a series of research papers, Mordukhovich has given basic tools (coderivatives, subdiffentials, normal cones, and calculus rules), fundamental results, and advanced techniques for qualitative studies of optimization and equilibrium problems Especially, the fourth chapter of the book is entirely devoted to such important properties of the solution set of parametric problems as the Lipschitz stability and metric regularity These properties indicate good behaviors of the multifunction in question The two models considered in that chapter of Mordukhovich’s book bear the names parametric constraint system and parametric variational system More discussions and references on implicit multifunction theorems can be found in the books viii ...VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY INSTITUTE OF MATHEMATICS DUONG THI KIM HUYEN STABILITY OF SOME CONSTRAINT SYSTEMS AND OPTIMIZATION PROBLEMS Speciality: Applied Mathematics... regularity, and the Robinson stability of solution maps of constraint and variational systems Results on these stability properties are applied to studying the solution stability of linear complementarity... Linear Constraint Systems 2.2 The Solution Maps of Parametric Linear Constraint Systems 11 2.3 Stability Properties of Generalized Linear Inequality Systems 19 2.4 The Solution Maps of Linear