This workshop was organized to mark Martine Labbé's 50th birthday. The aim of the workshop was to provide a high quality forum for the presentation of results, exchanges of ideas, scientific discussions on methodologies, computational issues and advanced applications in the area of mathematical programming.The research activities of Martine Labbé cover many aspects of mathematical programming with a special emphasis on combinatorial and network optimization. The main fields of applications in her work are location theory, communication network planning, traffic and transportation models, bilevel programming and production planning.The workshop had sessions dedicated to Location, Routing, Stochastic Optimization, Pricing and Auctions, Models for Competition, Combinatorial Optimization, Nonlinear Optimization, and Heuristics and Applications.Among the papers submitted for this special issue, 7 papers were finally accepted for inclusion. The contents of this issue are organized as follows.