Integer Programming and Combinatorial Optimization

Volume 3064 of the series Lecture Notes in Computer Science pp 196-205

A Faster Exact Separation Algorithm for Blossom Inequalities

  • Adam N. LetchfordAffiliated withDepartment of Management Science, Lancaster University
  • , Gerhard ReineltAffiliated withInstitut für Informatik, University of Heidelberg
  • , Dirk Oliver TheisAffiliated withInstitut für Informatik, University of Heidelberg

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In 1982, Padberg and Rao gave a polynomial-time separation algorithm for b-matching polyhedra. The current best known implementations of their separation algorithm run in \({\cal O}(|V|^2|E| \log (|V|^2/|E|))\) time when there are no edge capacities, but in \({\cal O}(|V||E|^2 \log (|V|^2/|E|))\) time when capacities are present.

We propose a new exact separation algorithm for the capacitated case which has the same running time as for the uncapacitated case. For the sake of brevity, however, we will restrict our introduction to the case of perfect 1-capacitated b-matchings, which includes, for example, the separation problem for perfect 2-matchings. As well as being faster than the Padberg-Rao approach, our new algorithm is simpler and easier to implement.


matching polyhedra separation