forest graph

Optimal Macroitem Sequences in the Precedence Constrained Knapsack Problem

  • Valerio Dose
  • Fabio Furini
  • Marco Locatelli
    • Categories Combinatorial Optimization, Graphs and Matroids, Linear Programming Tags , , ,

    The Precedence Constrained Knapsack Problem (PCKP) asks for a maximum-profit subset of items, subject to a knapsack capacity constraint and precedence constraints encoded by a directed acyclic graph. We study the structure of optimal solutions of the Linear Programming (LP) relaxation of the natural Integer Linear Programming formulation of the PCKP. We introduce the notion … Read more

    Exact SDP relaxations of quadratically constrained quadratic programs with forest structures

  • Godai Azuma
  • Mituhiro Fukuda
  • Sunyoung Kim
  • Makoto Yamashita
    • Categories Global Optimization, Semi-definite Programming Tags , , ,

    We study the exactness of the semidefinite programming (SDP) relaxation of quadratically constrained quadratic programs (QCQPs). With the aggregate sparsity matrix from the data matrices of a QCQP with $n$ variables, the rank and positive semidefiniteness of the matrix are examined. We prove that if the rank of the aggregate sparsity matrix is not less … Read more