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Proceedings of the 17Th Cologne-Twente Workshop on Graphs and Combinatorial Optimization Proceedings of the 17th Cologne-Twente Workshop on Graphs and Combinatorial Optimization Editors: Johann Hurink Stefan Klootwijk Bodo Manthey Victor Reijnders Martijn Schoot Uiterkamp Enschede, Netherlands, July 1{3, 2019 Editors Johann Hurink Stefan Klootwijk Bodo Manthey Victor Reijnders Martijn Schoot Uiterkamp CTW 2019 Proceedings of the 17th Cologne-Twente Workshop on Graphs and Combinatorial Optimiza- tion J.L. Hurink, S. Klootwijk, B. Manthey, V.M.J.J. Reijnders, M.H.H. Schoot Uiterkamp (eds.) Enschede, University of Twente, Faculty of Electrical Engineering, Mathematics and Computer Science 1{3 July 2019 ISSN 2590-0870 DSI Workshop Proceedings Series (online) WP19-01 https://www.utwente.nl/en/digital-society/ c Copyright 2019; University of Twente, Enschede, Netherlands 17th Cologne-Twente Workshop on Graphs and Combinatorial Optimization (CTW 2019) CTW 2019 takes place at the University of Twente, Enschede, Netherlands, from July 1 to July 3, 2019. This volume collects the extended abstracts of the contributions that have been selected for presentation at the workshop. As it was the case with previous CTWs, we will edit a special edition of Discrete Applied Mathematics for CTW 2019. Hereby, we invite all participants to submit full-length papers related to the topics of the workshop. Program Committee: Ali F. Alkaya (Marmara University, Istanbul, Turkey) • Alberto Ceselli (Universit`adegli Studi di Milano, Italy) • Roberto Cordone (Universit`adegli Studi di Milano, Italy) • Ekrem Duman (Ozye˘ginUniversity,¨ Istanbul, Turkey) • Johann L. Hurink (University of Twente, Enschede, Netherlands, co-chair) • Leo Liberti (Ecole´ Polytechnique, Paris, France) • Bodo Manthey (University of Twente, Enschede, Netherlands, co-chair) • Gaia Nicosia (Universit`adegli studi Roma Tre, Italy) • Andrea Pacifici (Universit`adegli Studi di Roma \Tor Vergata", Italy) • Stefan Pickl (Universit¨atder Bundeswehr M¨unchen, Germany) • Hubert Randerath (TH K¨oln,Germany) • Giovanni Righini (Universit`adegli Studi di Milano, Italy) • Heiko R¨oglin(University of Bonn, Germany) • Oliver Schaudt (RWTH Aachen University, Germany) • Rainer Schrader (University of Cologne, Germany) • Frank Vallentin (University of Cologne, Germany) • Organizing Committee: Johann L. Hurink • Stefan Klootwijk • Bodo Manthey • Marjo Mulder • Victor M.J.J. Reijnders • Martijn H.H. Schoot Uiterkamp • i List of Abstracts H¨useyinAcan, Sankardeep Chakraborty, Seungbum Jo, Srinivasa Rao Satti Succinct Data Structures for Families of Interval Graphs ............... 1 Tommaso Adamo, Gianpaolo Ghiani, Emanuela Guerriero An enhanced lower bound for the Time-Dependent Traveling Salesman Problem . 5 Amotz Bar-Noy, Toni B¨ohnlein,David Peleg, Dror Rawitz Vertex-Weighted Realizations of Graphs ........................ 9 Wissal Ben Amor, Amal Gassara, Ismael Bouassida Rodriguez Extending Bigraphical Language with Labels ...................... 13 Christoph Buchheim, Dorothee Henke The robust bilevel continuous knapsack problem .................... 17 Marco Casazza, Alberto Ceselli, Giovanni Righini A single machine on-time-in-full scheduling problem . 21 Martina Cerulli, Claudia D'Ambrosio, Leo Liberti On aircraft deconfliction by bilevel programming ................... 25 Victor Cohen, Axel Parmentier Linear programming for Decision Processes with Partial Information . 29 Matteo Cosmi, Gaia Nicosia, Andrea Pacifici Lower bounds for a meal pickup-and-delivery scheduling problem . 33 Matthias Feldotto, Pascal Lenzner, Louise Molitor, Alexander Skopalik From Hotelling to Load Balancing: Approximation and the Principle of Minimum Differentiation ...................................... 37 Samuel Fiorini, Krystal Guo, Marco Macchia, Matthias Walter Lower Bound Computations for the Nonnegative Rank . 41 Luisa Frickes, Simone Dantas, At´ılioG. Luiz The Graceful Game ................................... 45 Dami´an-EmilioGibaja-Romero, Vanessa Cruz-Molina A colorful generalization for the Poison Game .................... 49 Benjamin Gras, Mathieu Liedloff Enumeration of Minimal Connected Dominating Sets in chordal bipartite graphs . 53 Alexander Grigoriev, Tim A. Hartmann, Stefan Lendl, Gerhard J. Woeginger Dispersing obnoxious facilities on a graph ....................... 57 iii Zhiwei Guo, Hajo Broersma, Binlong Li, Shenggui Zhang Compatible spanning circuits in edge-colored Fan-type graphs . 61 Nili Guttmann-Beck, Michal Stern Clustered Feasibility by Breaking ............................ 65 Zacharias Heinrich, R¨udigerReischuk Improved Dynamic Kernels for Hitting-Set ...................... 69 Michael A. Henning, Arti Pandey, Vikash Tripathi Algorithm and Hardness Result for Semipaired Domination in Graphs . 73 Gabriele Iommazzo, Claudia D'Ambrosio, Antonio Frangioni, Leo Liberti Algorithmic configuration by learning and optimization . 77 Reinoud Joosten, Eduardo Lalla-Ruiz Inductive Shapley values in cooperative transportation games . 81 Saeid Kazemzadeh Azad Combinatorial optimization in structural engineering: recent trends and future needs 85 Thomas Lachmann, Stefan Lendl Efficient Algorithms for the Recoverable (Robust) Selection Problem . 87 Stefan Lendl, Britta Peis, Veerle Timmermans Matroid Sum with Cardinality Constraints on the Intersection . 91 Dmitrii Lozovanu, Stefan Pickl Stationary Nash Equilibria Conditions for Stochastic Positional Games . 95 Radu Mincu, Camelia Obreja, Alexandru Popa The graceful chromatic number for some particular classes of graphs . 99 Samuel Mohr On Uniquely Colourable Graphs ............................. 103 Gaia Nicosia, Andrea Pacifici, Ulrich Pferschy, Edoardo Polimeno, Giovanni Righini Optimally rescheduling jobs under LIFO constraints . 107 Temel Oncan,¨ M. Hakan Aky¨uz, I._ Kuban Altınel An exact algorithm for the maximum weight perfect matching problem with conflicts 111 Xavier Ouvrard, Jean-Marie Le Goff, St´ephaneMarchand-Maillet Multi-diffusion in Hb-graphs ............................... 115 Axel Parmentier, Victor Cohen, Vincent Lecl`ere,Guillaume Obozinski, Joseph Salmon Mathematical programming for influence diagrams . 119 Julie Poullet, Axel Parmentier Ground staff shift planning under delay uncertainty at Air France . 123 Andreas Schwenk On the Problem Class of Optimal Technology Implementation into a Multisectoral Energy System (OTIMES) ................................ 127 Florian Thaeter Hardness of k-anonymous microaggregation . 131 iv Benito van der Zander, Johannes Textor, Maciej Li´skiewicz Graphical Methods for Finding Instrumental Variables . 135 Wei Zheng, Hajo Broersma, Ligong Wang Toughness and forbidden subgraphs for hamiltonian-connected graphs . 139 Qiannan Zhou, Hajo Broersma, Ligong Wang, Yong Lu On sufficient spectral radius conditions for hamiltonicity . 143 v Succinct Data Structures for Families of Interval Graphs H¨useyinAcan1, Sankardeep Chakraborty2, Seungbum Jo3, and Srinivasa Rao Satti4 1Drexel University, USA 2RIKEN Center for Advanced Intelligence Project, Japan 3University of Siegen, Germany 4Seoul National University, South Korea Abstract We consider the problem of designing succinct data structures for interval graphs with n vertices while supporting degree, adjacency, neighborhood and shortest path queries in optimal time. Towards showing succinctness, we first show that at least n log n 2n log log n O(n) bits1. are necessary to represent any unlabeled interval graph G with n vertices,− answering− an open problem of Yang and Pippenger [Proc. Amer. Math. Soc. 2017]. This is augmented by a data structure of size n log n + O(n) bits while supporting not only the above queries optimally but also capable of executing various combinatorial algorithms (like proper coloring, maximum independent set etc.) on interval graphs efficiently. Finally, we extend our ideas to other variants of interval graphs, for example, proper/unit, k-improper interval graphs, and circular-arc graphs, and design succinct data structures for these graph classes as well along with supporting queries on them efficiently. 1 Introduction A simple undirected graph G is called an interval graph if its vertices can be assigned to intervals on the real line so that two vertices are adjacent in G if and only if their assigned intervals intersect. The set of intervals assigned to the vertices of G is called a realization of G. These graphs were first introduced by Haj´os[5] who also asked for the characterization of them. The same problem was also asked, independently, by Benser [2] while studying the structure of genes. Interval graphs naturally appear in a variety of contexts, for example, operations research and scheduling theory, biology especially in physical mapping of DNA, temporal reasoning and many more. We refer the reader to [4] for a thorough treatment of interval graphs and its applications. Eventually answering the question of Haj´os[5], several researchers came up with different characterizations of interval graphs, including linear time algorithms for recognizing them; see, for example, [4, Chapter 8] for characterizations, and linear time algorithms. Moreover, exploiting the special structure of interval graphs, many otherwise NP-hard problems in general graphs are also shown to have polynomial time algorithms for interval graphs [4]. These include computing maximum independent set, reporting a proper coloring, returning a maximum clique etc. In spite of having many applications in practically motivated problems, we are not aware of, to the best of our knowledge, any study of interval graphs from the point of view of succinct data structures where
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