Article
Mathematics, Applied
Kazuo Murota, Akihisa Tamura
Summary: This paper discusses the important issue of discrete Fenchel duality in discrete convex analysis. It establishes a Fenchel-type min-max formula for a pair of integer-valued integrally convex and separable convex functions, with the proof based on Fourier-Motzkin elimination.
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS
(2022)
Article
Operations Research & Management Science
M. D. Fajardo, J. Vidal
Summary: In this paper, we propose two Fenchel-type dual problems for a DC optimization primal one. Based on the c-conjugation scheme, which is suitable for evenly convex functions, these problems are constructed. We investigate the characterizations of weak, strong, and stable strong duality for both pairs of primal-dual problems. Additionally, we provide conditions that relate to the existence of strong and stable strong duality for both pairs.
Article
Mathematics, Applied
Kazuo Murota, Kenjiro Takazawa
Summary: The shortest bibranching problem is a common generalization of the minimum-weight edge cover problem in bipartite graphs and the minimum-weight arborescence problem in directed graphs, which can be solved through different formulations such as primal-dual algorithms and valuated matroid intersection formulation. Research has shown a connection between these formulations, allowing for the transformation of optimal solutions through Benders decomposition and construction of optimal solutions.
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS
(2021)
Article
Mathematics, Applied
Christoph Hunkenschroder, Sebastian Pokutta, Robert Weismantel
Summary: This article discusses the problem of minimizing a convex function over a set using a matrix W and an unknown convex function g. It focuses on separable convex functions and sharp convex functions, and presents a proximity theorem that shows the closeness between integral minimum and continuous minimum for these functions. This theorem plays a key role in developing an algorithm for detecting an integer minimum.
SIAM JOURNAL ON OPTIMIZATION
(2023)
Article
Operations Research & Management Science
Andras Frank, Kazuo Murota
Summary: This paper presents a min-max formula for the minimum of an integer-valued separable discrete convex function. The framework also covers a wide range of combinatorial optimization problems.
MATHEMATICS OF OPERATIONS RESEARCH
(2021)
Article
Operations Research & Management Science
Hadi Khatibzadeh, Mohsen Rahimi Piranfar, Jamal Rooin
Summary: This paper studies the asymptotic behavior of the diagonal proximal point algorithms controlled by a sequence of maximally monotone operators. By imposing a summability condition on the Brezis-Haraux functions of the operator sequence, several ergodic and weak convergence results are obtained in the monotone and subgradient cases, and some strong convergence results are also presented. The results in this paper include discrete versions of classical results and unify and improve existing results.
Article
Mathematics, Applied
Satoshi Hayakawa, Ken'ichiro Tanaka
Summary: In this paper, we investigate the approximation formulas proposed by Tanaka & Sugihara (IMA J. Numer. Anal. 39(4):1957-1984, 2019) in weighted Hardy spaces, which are analytic function spaces with certain asymptotic decay. Using the criterion of minimum worst error of n-point approximation formulas, we show that the formulas are nearly optimal. Additionally, we obtain upper bounds for the approximation errors that match the existing heuristic bounds in asymptotic order using a duality theorem for the minimization problem of potential energy.
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS
(2023)
Article
Operations Research & Management Science
Tim Hoheisel, Elliot Paquette
Summary: In this paper, we provide necessary and sufficient conditions for the existence of line segments (or flats) in the sphere of the nuclear norm using simultaneous polarization and a refined expression for the subdifferential of the nuclear norm. We also establish point-based necessary and sufficient conditions for uniqueness of solutions in minimizing the nuclear norm over an affine subspace. Additionally, we present an alternative set of sufficient conditions for uniqueness based on the subdifferential of the nuclear norm and the range of the problem-defining linear operator.
JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS
(2023)
Article
Engineering, Multidisciplinary
Y. I. N. G. R. A. N. G. Xu, S. H. E. N. G. J. I. E. LI
Summary: This paper addresses an optimization problem involving the difference of two Phi(c)-convex functions, with a set constraint and a conic constraint. In the framework of c-conjugacy, the authors construct the generalized Lagrange and Fenchel dual problems using the perturbation approach and provide complete characterizations of strong duality for these dual problems. As applications, corresponding results for minimizing the difference of two evenly quasiconvex functions are also given.
JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION
(2022)
Article
Engineering, Multidisciplinary
Yingrang Xu, Shengjie Li
Summary: This paper addresses an optimization problem where the objectives are defined as the difference of two Phi(c)-convex functions, incorporating a set constraint and a conic constraint. Employing the framework of c-conjugacy, the paper constructs the generalized Lagrange and Fenchel dual problems using the perturbation approach. Further, the paper obtains complete characterizations of the strong duality for these two dual problems. Additionally, the paper provides corresponding results for the minimization of the difference of two evenly quasiconvex functions.
JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION
(2023)
Article
Mathematics, Applied
Gabriel Rioux, Rustum Choksi, Tim Hoheisel, Pierre Marechal, Christopher Scarvelis
Summary: This article introduces the application of maximum entropy on the mean (MEM) to image deblurring and point spread function estimation, shifting the paradigm towards regularization at the level of the probability distribution on the space of images. The method is simple, capable of handling large blurs, and has potential for generalization and modifications.
Article
Mathematics
M. H. Khalifeh, Abdol-Hossein Esfahanian
Summary: This passage discusses the problem of finding the minimum weight sum in a vertex and edge weighted graph G. It introduces the concept of best switch (BS) and defines three notions: convexity, discrete derivative, and discrete integral for VEW graphs. An algorithm is also proposed to solve the BS problem for positively VEW trees.
Article
Mathematics, Applied
Kazuo Murota, Akiyoshi Shioura
Summary: This paper investigates fundamental issues related to minimization for a class of discrete quasi-convex functions called semi-strictly quasi M-#-convex functions, including optimality condition by local optimality, minimizer cut property, geodesic property, and proximity property. Emphasis is put on comparisons with (usual) M-#-convex functions.
JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS
(2023)
Article
Operations Research & Management Science
Wataru Takahashi, Yukio Takeuchi
Summary: This paper discusses the Fenchel duality formula, Brondsted-Rockafellar's theorem, and a minimization theorem in a Banach space. The focus is on the proofs of the Ekeland variational principle and Takahashi's nonconvex minimization theorem in different spaces.
Article
Mathematics, Applied
Guillaume Carlier
Summary: This note discusses applications of a simple quantitative form of the Fenchel-Young inequality in Hilbert spaces for both convex functions and Fitzpatrick functions of maximal monotone operators. The initial motivation for this study comes from a stability question in optimal transport. By deriving a simple and constructive proof of the Brondsted-Rockafellar theorem and a perturbed primal-dual attainment result in Hilbert spaces from the quantitative form of the Fenchel-Young inequality.
SIAM JOURNAL ON OPTIMIZATION
(2023)