@inproceedings{BorndoerferNeumannPfetsch2009, author = {Bornd{\"o}rfer, Ralf and Neumann, Marika and Pfetsch, Marc}, title = {Line Planning and Connectivity}, booktitle = {Models and Algorithms for Optimization in Logistics}, number = {09261}, editor = {Barnhart, Cynthia and Clausen, Uwe and Lauther, Ulrich and M{\"o}hring, Rolf}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, Germany}, address = {Dagstuhl, Germany}, year = {2009}, language = {en} } @inproceedings{BorndoerferNeumannPfetsch2009, author = {Bornd{\"o}rfer, Ralf and Neumann, Marika and Pfetsch, Marc}, title = {The Line Connectivity Problem}, booktitle = {Operations Research Proceedings 2008}, editor = {Fleischmann, Bernhard and Borgwardt, Karl and Klein, Robert and Tuma, Axel}, publisher = {Springer-Verlag}, pages = {557 -- 562}, year = {2009}, language = {en} } @misc{BorndoerferNeumannPfetsch2009, author = {Bornd{\"o}rfer, Ralf and Neumann, Marika and Pfetsch, Marc}, title = {The Steiner Connectivity Problem}, issn = {1438-0064}, doi = {10.1007/s10107-012-0564-5}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11171}, number = {09-07}, year = {2009}, abstract = {The Steiner connectivity problem is a generalization of the Steiner tree problem. It consists in finding a minimum cost set of simple paths to connect a subset of nodes in an undirected graph. We show that polyhedral and algorithmic results on the Steiner tree problem carry over to the Steiner connectivity problem, namely, the Steiner cut and the Steiner partition inequalities, as well as the associated polynomial time separation algorithms, can be generalized. Similar to the Steiner tree case, a directed formulation, which is stronger than the natural undirected one, plays a central role.}, language = {en} } @misc{Neumann2009, author = {Neumann, Marika}, title = {Fare Planning for Public Transport}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11144}, number = {09-04}, year = {2009}, abstract = {In this paper we investigate the fare planning model for public transport, which consists in designing a system of fares maximizing the revenue. We discuss a discrete choice model in which passengers choose between different travel alternatives to express the demand as a function of fares. Furthermore, we give a computational example for the city of Potsdam and discuss some theoretical aspects.}, language = {en} }