bilevel optimization

A Variational Analysis Approach for Bilevel Hyperparameter Optimization with Sparse Regularization

  • David Villacís
  • Pedro Pérez-Aros
  • Emilio Vilches
    • Categories Bilevel Optimization, Nonsmooth Optimization, Optimization in Data Science Tags , , ,

    We study a bilevel optimization framework for hyperparameter learning in variational models, with a focus on sparse regression and classification tasks. In particular, we consider a weighted elastic-net regularizer, where feature-wise regularization parameters are learned through a bilevel formulation. A key novelty of our approach is the use of a Forward-Backward (FB) reformulation of the … Read more

    Branch-and-Cut for Mixed-Integer Nash Equilibrium Problems

  • Alois Duguet
  • Tobias Harks
  • Martin Schmidt
  • Julian Schwarz
    • Categories (Mixed) Integer Linear Programming, Bilevel Optimization, Game Theory Tags , , , ,

    We consider Nash equilibrium problems with mixed-integer variables in which each player solves a mixed-integer optimization problem parameterized in the rivals’ strategies. We distinguish between standard Nash equilibrium problems (NEP), where the parameterization acts only on the players’ cost functions and generalized Nash equilibrium problems (GNEPs), where, additionally, the strategy spaces of the players may … Read more

    A stochastic gradient method for trilevel optimization

  • Tommaso Giovannelli
  • Griffin D. Kent
  • Luis Nunes Vicente
    • Categories Multi-Criteria Optimization Tags , , ,

    With the success that the field of bilevel optimization has seen in recent years, similar methodologies have started being applied to solving more difficult applications that arise in trilevel optimization. At the helm of these applications are new machine learning formulations that have been proposed in the trilevel context and, as a result, efficient and … Read more

    Mathematical programs with complementarity constraints and application to hyperparameter tuning for nonlinear support vector machines

  • Samuel Ward
  • Alain Zemkoho
  • Selin Damla Ahipasaoglu
    • Categories Bilevel Optimization, Complementarity and Variational Inequalities, Optimization in Data Science Tags , , , , ,

    We consider the Mathematical Program with Complementarity Constraints (MPCC). One of the main challenges in solving this problem is the systematic failure of standard Constraint Qualifications (CQs). Carefully accounting for the combinatorial nature of the complementarity constraints, tractable versions of the Mangasarian Fromovitz Constraint Qualification (MFCQ) have been designed and widely studied in the literature. … Read more

    On Coupling Constraints in Pessimistic Linear Bilevel Optimization

  • Dorothee Henke
  • Henri Lefebvre
  • Martin Schmidt
  • Johannes Thürauf
    • Categories Bilevel Optimization Tags , , ,

    The literature on pessimistic bilevel optimization with coupling constraints is rather scarce and it has been common sense that these problems are harder to tackle than pessimistic bilevel problems without coupling constraints. In this note, we show that this is not the case. To this end, given a pessimistic problem with coupling constraints, we derive … Read more

    A Computational Study for Solving Decision-Dependent Robust Problems as Bilevel Optimization Problems

  • Henri Lefebvre
  • Martin Schmidt
  • Simon Stevens
  • Johannes Thürauf
    • Categories Bilevel Optimization, Robust Optimization Tags , , ,

    Both bilevel and robust optimization are established fields of mathematical optimization and operations research. However, only until recently, the similarities in their mathematical structure has neither been studied theoretically nor exploited computationally. Based on the recent results by Goerigk et al. (2025), this paper is the first one that provides an extensive computational study for … Read more

    An Oracle-based Approach for Price-setting Problems in Logistics

  • Nele Pommerening
  • Maja Hügging
  • Dorothee Henke
  • Christoph Buchheim
  • Uwe Clausen
    • Categories Integer Programming, Transportation Tags , , ,

    We study a bilevel hub location problem where on the upper level, a shipment service provider –the leader–builds a transportation network and sets the prices of shipments on each possible transportation relation. Here, the leader has to take into account the customers’ reaction — the follower — who will only purchase transport services depending on … Read more

    A Single-Level Reformulation of Binary Bilevel Programs using Decision Diagrams

  • Sebastian Vasquez
  • Leonardo Lozano
  • Willem-Jan van Hoeve
    • Categories Bilevel Optimization, Combinatorial Optimization, Integer Programming Tags , ,

    Binary bilevel programs are notoriously difficult to solve due to the absence of strong and efficiently computable relaxations. In this work, we introduce a novel single-level reformulation of these programs by leveraging a network flow-based representation of the follower’s value function, utilizing decision diagrams and linear programming duality. This approach enables the development of scalable … Read more

    Two-Stage Distributionally Robust Optimization: Intuitive Understanding and Algorithm Development from the Primal Perspective

  • Zhengsong Lu
  • Bo Zeng
    • Categories Robust Optimization, Semi-infinite Programming Tags , ,

    In this paper, we study the two-stage distributionally robust optimization (DRO) problem from the primal perspective. Unlike existing approaches, this perspective allows us to build a deeper and more intuitive understanding on DRO, to leverage classical and well established solution methods and to develop a general and fast decomposition algorithm (and its variants), and to … Read more

    Solving Multi-Follower Mixed-Integer Bilevel Problems with Binary Linking Variables

  • Vladimir Stadnichuk
  • Arie M.C.A. Koster
    • Categories (Mixed) Integer Linear Programming, Cutting Plane Approaches, Network Optimization Tags , , , ,

    We study multi-follower bilevel optimization problems with binary linking variables where the second level consists of many independent integer-constrained subproblems. This problem class not only generalizes many classical interdiction problems but also arises naturally in many network design problems where the second-level subproblems involve complex routing decisions of the actors involved. We propose a novel … Read more