In many branch-and-price algorithms, the column generation subproblem consists of computing feasible constrained paths. In the capacitated arc-routing problem (CARP), elementarity constraints concerning the edges to be serviced and additional constraints resulting from the branch-and-bound...

The Mixed Capacitated General Routing Problem (MCGRP) is defined over a mixed graph, for which some vertices must be visited and some links must be traversed at least once. The problem consists of determining a set of least-cost vehicle routes that satisfy this requirement and respect the...

Column generation (CG) models have several advantages over compact formulations, namely, they provide better LP bounds, may eliminate symmetry, and can hide non-linearities in their subproblems. However, users also encounter drawbacks in the form of slow convergency a.k.a. the tailing-off effect...

We present two new methods to stabilize column-generation algorithms for the Temporal Knapsack Problem (TKP). Caprara et al. [Caprara A, Furini F, and Malaguti E (2013) Uncommon Dantzig-Wolfe Reformulation for the Temporal Knapsack Problem. INFORMS J. on Comp. 25(3):560–571] were the first to...

The minimum tour duration problem (MTDP) is the variant of the traveling salesman problem with time windows, which consists of finding a time window-feasible Hamiltonian path minimizing the tour duration. We present a new effective dynamic programming (DP)-based approach for the MTDP. When...

The traveling tournament problem (ttp) consists of finding a distance-minimal double round-robin tournament where the number of consecutive breaks is bounded. For solving the problem exactly, we propose a new branch-and-price approach. The starting point is a new compact formulation for the ttp....

The paper presents the results of a study performed by the Deutsche post endowed chair of optimization of distribution networks in collaboration with Deutsche Post World Net with the aim of improving the planning of letter mail delivery. Modelling and solution methods for real-world postman...