compact reformulation

Reformulation of a model for hierarchical divisive graph modularity maximization

  • Sonia Cafieri
  • Alberto Costa
  • Pierre Hansen
    • Categories Convex Optimization, Network Optimization, Quadratic Programming Tags , , ,

    Finding clusters, or communities, in a graph, or network is a very important problem which arises in many domains. Several models were proposed for its solution. One of the most studied and exploited is the maximization of the so called modularity, which represents the sum over all communities of the fraction of edges within these … Read more

    Single Item Lot-Sizing with Nondecreasing Capacities

  • Yves Pochet
  • Laurence A. Wolsey
    • Categories (Mixed) Integer Linear Programming, Polyhedra, Production and Logistics Tags , , ,

    We consider the single item lot-sizing problem with capacities that are non-decreasing over time. When the cost function is i) non-speculative or Wagner-Whitin (for instance, constant unit production costs and non-negative unit holding costs), and ii) the production set-up costs are non-increasing over time, it is known that the minimum cost lot-sizing problem is polynomially … Read more