Biography

Biography: In 2007, I received my PhD in mathematics from Ecole Polytechnique Fédérale de Lausanne(CH). From 2008 to 2009, I was a Postdoctoral Research Fellow at Columbia University (US) in the Department of Industrial Engineering and Operations Research. In 2009-2010, I was appointed as Assistant Professor at the University of Warwick (UK) in the Center for Discrete Mathematics and its Applications (DIMAP) and the Warwick Business School (WBS). From September 2010 to July 2015, I was an Associate Professor at the Université Paris Dauphine (F) in the Computer Science and Mathematics Department. Currently I am a Professor at the University of Fribourg (CH), where I am heading the Decision Support & Operations Research Group together with Marino Widmer in the Department of Informatics. In 2022, I joined the Smart Living Lab project with some members of my team.

My main research interests are:

• Structural and algorithmic graph theory
• Combinatorial optimization
• Computational complexity
• Mathematical Modeling

Phd Students:

• Nathanael Barrot: 2012 - 2015 (currently postdoc at RIKEN Research Center in Japan)
  (co-supervisor: Jérôme Lang (Université Paris Dauphine))
• Esther Galby: 2015 - 2020 (currently Assistant professor at Chalmers University of Technology, Sweden)
• Vera Fischer: 2018 - 2023 (co-supervision with Meritxell Pacheco, currently at La Poste)
• Felix Mann: 2019 -
• Felicia Lucke: 2020 - 2024
• Narmina Baghirova: 2020 - (co-supervision with David Schindl)
• Elise Bangerter: 2023 - (co-supervision with Meritxell Pacheco)

Visiting PhD students:

• Zakir Deniz (2017, Duzce University (Turkey))
• Pierre Hauweele (2018, Université de Mons (Belgium))
• Paloma Thomé de Lima (2018, University of Bergen (Norway))
• Carolina Goncalvez (20021, 2022, University of Buenos Aires (Argentina))

Member of PhD committees:

• Grégoire Cotté, Conservatoire National des Arts et Métiers, Paris, France (2016)
• Vasileios Papapanagiotu, Università della Svizzera Italiana, Lugano, Switzerland (2018)
• Gauvain Devillez, Université de Mons, Belgium (2022)
• Nikolaos Melissinos, Université Paris Dauphine PSL, France (2022)
• Valentin Bouquet, Conservatoire National des Arts et Métiers, Paris, France (2022)

Postdocs:

• Diana Sasaki: 2014 - 2015 (now Professor at Universidade do Estado do Rio de Janeiro (Brazil))
• Maria Pia Mazzoleni: August 2017 (now Docencia at Universidad Nacional La Plata (Argentina))
• Andrea Munaro: February - June 2018 (now Assistant Professor at University of Parma (Italy))
• Zakir Deniz: September - December 2019
• Meritxell Pacheco: January 2021 - August 2021 (now Senior Researcher and Lecturer at University of Fribourg (CH))
• Jérôme De Boeck: March 2022 - August 2023 (now Assistant Professor at HEC Liège, Belgium)
• Nour Elhouda Tellache: 2024 - 

Research and publications

• Publications
  137 publications

  2025 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2005

  Matching Cuts in Graphs of High Girth and H-Free Graphs
  Bernard Ries, Carl Feghali, Felicia Lucke, Daniël Paulusma, Algorithmica (2025) | Journal article

  Finding k-community structures in special graph classes
  David Schindl, Narmina Baghirova, Clément Dallard, Bernard Ries, Discrete Applied Mathematics (2024) | Journal article

  Dichotomies for Maximum Matching Cut: H-freeness, bounded diameter, bounded radius
  Bernard Ries, Felicia Lucke, Daniël Paulusma, Theoretical Computer Science (2024) | Journal article

  On blockers and transversals of maximum independent sets in co-comparability graphs
  Bernard Ries, Felicia Lucke, Discrete Applied Mathematics (2024) | Journal article

  Finding Matching Cuts in H-Free Graphs
  Bernard Ries, Felicia Lucke, Daniël Paulusma, Algorithmica (2023) | Journal article

  Using edge contractions to reduce the semitotal domination number
  Galby, E. and Lima, P.T. and Mann, F. and Ries, B., Theoretical Computer Science (2023) | Journal article

  Dichotomies for Maximum Matching Cut: H-Freeness, Bounded Diameter, Bounded Radius
  Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2023) | Other

  Finding k-community structures in special graph classes
  Baghirova, N. and Dallard, C. and Ries, B. and Schindl, D. , Research Square (2023) | Other

  Dichotomies for Maximum Matching Cut: H-Freeness, Bounded Diameter, Bounded Radius
  Lucke, F. and Paulusma, D. and Ries, B., Leibniz International Proceedings in Informatics, LIPIcs: (2023) | Conference

  Preface
  Paulusma, D. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2023) | Book

  Dichotomies for Maximum Matching Cut: H-Freeness, Bounded Diameter, Bounded Radius
  Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2023) | Other

  Matching Cuts in Graphs of High Girth and H-Free Graphs
  Feghali, Carl and Lucke, Felicia and Paulusma, Daniël and Ries, Bernard, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023) | Conference

  On some special classes of contact B₀-VPG graphs
  Bonomo-Braberman, F. and Mazzoleni, M.P. and Rean, M.L. and Ries, B., Discrete Applied Mathematics (2022) | Journal article

  On The Complexity of Matching Cut for Graphs of Bounded Radius and H-Free Graphs
  Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2022) | Other

  FINDING K-COMMUNITY STRUCTURES IN SPECIAL GRAPH CLASSES
  Baghirova, N. and Dallard, C. and Ries, B. and Schindl, D. , arXiv (2022) | Other

  LOCALLY CHECKABLE PROBLEMS PARAMETERIZED BY CLIQUE-WIDTH
  Baghirova, N. and Gonzalez, C.L. and Ries, B. and Schindl, D. , arXiv (2022) | Other

  Finding Matching Cuts in H-Free Graphs
  Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2022) | Other

  Matching Cuts in Graphs of High Girth and H-Free Graphs
  Feghali, C. and Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2022) | Other

  Finding Matching Cuts in H-Free Graphs
  Lucke, F. and Paulusma, D. and Ries, B., Leibniz International Proceedings in Informatics, LIPIcs: (2022) | Conference

  On The Complexity of Matching Cut for Graphs of Bounded Radius and H-Free Graphs
  Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2022) | Other

  On the complexity of matching cut for graphs of bounded radius and H-free graphs
  Lucke, F. and Paulusma, D. and Ries, B., Theoretical Computer Science (2022) | Journal article

  Locally Checkable Problems Parameterized by Clique-Width
  Baghirova, N. and Gonzalez, C.L. and Ries, B. and Schindl, D., Leibniz International Proceedings in Informatics, LIPIcs: (2022) | Conference

  Matching Cuts in Graphs of High Girth and H-Free Graphs
  Feghali, C. and Lucke, F. and Paulusma, D. and Ries, B. , arXiv (2022) | Other

  CPG graphs: Some structural and hardness results
  Nicolas Champseix and Esther Galby and Andrea Munaro and Bernard Ries, Discrete Applied Mathematics (2021) | Journal article

  Using edge contractions to reduce the semitotal domination number
  Galby, E. and Lima, P.T. and Mann, F. and Ries, B. , arXiv (2021) | Other

  Reducing the domination number of (P₃+kP₂)-free graphs via one edge contraction
  Galby, E. and Mann, F. and Ries, B., Discrete Applied Mathematics (2021) | Journal article

  Reducing the domination number of graphs via edge contractions and vertex deletions
  Galby, E. and Lima, P.T. and Ries, B., Discrete Mathematics (2021) | Journal article

  Blocking total dominating sets via edge contractions
  Galby, E. and Mann, F. and Ries, B., Theoretical Computer Science (2021) | Journal article

  New progress in combinatorial optimization
  Chen, B. and Martello, S. and Ries, B., Discrete Applied Mathematics (2021) | Journal article

  Using edge contractions to reduce the semitotal domination number
  Galby, E. and Lima, P.T. and Mann, F. and Ries, B. , arXiv (2021) | Other

  Semitotal Domination: New hardness results and a polynomial-time algorithm for graphs of bounded mim-width
  Galby, E. and Munaro, A. and Ries, B., Theoretical Computer Science (2020) | Journal article

  Blocking total dominating sets via edge contractions
  Galby, E. and Mann, F. and Ries, B. , arXiv (2020) | Other

  On Some Subclasses of Split B₁ -EPG Graphs
  Deniz, Z. and Nivelle, S. and Ries, B. and Schindl, D. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2020) | Book

  Blocking total dominating sets via edge contractions
  Galby, E. and Mann, F. and Ries, B. , arXiv (2020) | Other

  Critical vertices and edges in H-free graphs
  Paulusma, D. and Picouleau, C. and Ries, B., Discrete Applied Mathematics (2019) | Journal article

  Detecting strong cliques
  Hujdurovi?, A. and Milani?, M. and Ries, B., Discrete Mathematics (2019) | Journal article

  Classifying k-edge colouring for H-free graphs
  Galby, E. and Lima, P.T. and Paulusma, D. and Ries, B., Information Processing Letters (2019) | Journal article

  Preface: Tenth International Colloquium on Graphs and Optimization (GO X), 2016
  Crama, Y. and Gendron, B. and Ries, B., Discrete Applied Mathematics (2019) | Journal article

  Proper circular arc graphs as intersection graphs of pathson a grid
  Galby, E. and Mazzoleni, M.P. and Ries, B., Discrete Applied Mathematics (2019) | Journal article

  Blocking dominating sets for H-free graphs via edge contractions
  Galby, E. and Lima, P.T. and Ries, B., Leibniz International Proceedings in Informatics, LIPIcs: (2019) | Conference

  Reducing the domination number of graphs via edge contractions
  Galby, E. and Lima, P.T. and Ries, B., Leibniz International Proceedings in Informatics, LIPIcs: (2019) | Conference

  Maximum eccentric connectivity index for graphs with given diameter
  Hauweele, P. and Hertz, A. and Mélot, H. and Ries, B. and Devillez, G., Discrete Applied Mathematics (2019) | Journal article

  Blocking dominating sets for H-free graphs via edge contractions
  Galby, E. and Lima, P.T. and Ries, B. , arXiv (2019) | Other

  Reducing the domination number of graphs via edge contractions
  Galby, E. and Paloma, T.L. and Ries, B. , arXiv (2019) | Other

  CPG graphs: Some structural and hardness results
  Champseix, N. and Galby, E. and Munaro, A. and Ries, B. , arXiv (2019) | Other

  On the parameterized complexity of k-edge colouring
  Galby, E. and Lima, P.T. and Paulusma, D. and Ries, B. , arXiv (2019) | Other

  Blocking dominating sets for H-free graphs via edge contractions
  Galby, E. and Lima, P.T. and Ries, B. , arXiv (2019) | Other

  CPG graphs: Some structural and hardness results
  Champseix, N. and Galby, E. and Munaro, A. and Ries, B. , arXiv (2019) | Other

  Reducing the domination number of graphs via edge contractions
  Galby, E. and Paloma, T.L. and Ries, B. , arXiv (2019) | Other

  On the parameterized complexity of k-edge colouring
  Galby, E. and Lima, P.T. and Paulusma, D. and Ries, B. , arXiv (2019) | Other

  On the bend number of circular-arc graphs as edge intersection graphs of paths on a grid
  Alcón, L. and Bonomo, F. and Durán, G. and Gutierrez, M. and Mazzoleni, M.P. and Ries, B. and Valencia-Pabon, M., Discrete Applied Mathematics (2018) | Journal article

  Upper Domination: Towards a Dichotomy Through Boundary Properties
  AbouEisha, H. and Hussain, S. and Lozin, V. and Monnot, J. and Ries, B. and Zamaraev, V., Algorithmica (2018) | Journal article

  On contact graphs of paths on a grid
  Deniz, Z. and Galby, E. and Munaro, A. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2018) | Book

  On split B<inf>1</inf> -EPG graphs
  Deniz, Z. and Nivelle, S. and Ries, B. and Schindl, D. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2018) | Book

  Dominating induced matchings in graphs containing no long claw
  Hertz, A. and Lozin, V. and Ries, B. and Zamaraev, V. and de Werra, D., Journal of Graph Theory (2018) | Journal article

  Contraction and deletion blockers for perfect graphs and H-free graphs
  Diner, Ö.Y. and Paulusma, D. and Picouleau, C. and Ries, B., Theoretical Computer Science (2018) | Journal article

  Characterising Chordal ContactB<inf>0</inf>-VPG Graphs
  Bonomo, F. and Mazzoleni, M.P. and Rean, M.L. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2018) | Book

  Graphs vertex-partitionable into strong cliques
  Hujdurovi?, A. and Milani?, M. and Ries, B., Discrete Mathematics (2018) | Journal article

  Complexity and Algorithms for Finding a Perfect Phylogeny from Mixed Tumor Samples
  Hujdurovic, A. and Kacar, U. and Milanic, M. and Ries, B. and Tomescu, A.I., IEEE/ACM Transactions on Computational Biology and Bioinformatics (2018) | Journal article

  Planar CPG graphs
  Champseix, N. and Galby, E. and Ries, B. , arXiv (2018) | Other

  Semitotal Domination: New hardness results and a polynomial-Time algorithm for graphs of bounded mim-width
  Galby, E. and Munaro, A. and Ries, B. , arXiv (2018) | Other

  Classifying k-edge colouring for H-free graphs
  Galby, E. and Lima, P.T. and Paulusma, D. and Ries, B. , arXiv (2018) | Other

  Proper circular arc graphs as intersection graphs of paths on a grid
  Galby, E. and Mazzoleni, M.P. and Ries, B. , arXiv (2018) | Other

  Detecting strong cliques
  Hujdurovi?, A. and Milani?, M. and Ries, B. , arXiv (2018) | Other

  On some special classes of contact B₀-VPG graphs
  Bonomo, F. and Mazzoleni, M.P. and Rean, M.L. and Ries, B. , arXiv (2018) | Other

  On contact graphs of paths on a Grid
  Deniz, Z. and Galby, E. and Munaro, A. and Ries, B. , arXiv (2018) | Other

  On some special classes of contact B₀-VPG graphs
  Bonomo-Braberman, F. and Mazzoleni, M.P. and Rean, M.L. and Ries, B. , arXiv (2018) | Other

  Proper circular arc graphs as intersection graphs of paths on a grid
  Galby, E. and Mazzoleni, M.P. and Ries, B. , arXiv (2018) | Other

  Planar CPG graphs
  Champseix, N. and Galby, E. and Ries, B. , arXiv (2018) | Other

  Classifying k-edge colouring for H-free graphs
  Galby, E. and Lima, P.T. and Paulusma, D. and Ries, B. , arXiv (2018) | Other

  Detecting strong cliques
  Hujdurovi?, A. and Milani?, M. and Ries, B. , arXiv (2018) | Other

  Semitotal Domination: New hardness results and a polynomial-Time algorithm for graphs of bounded mim-width
  Galby, E. and Munaro, A. and Ries, B. , arXiv (2018) | Other

  On contact graphs of paths on a Grid
  Deniz, Z. and Galby, E. and Munaro, A. and Ries, B. , arXiv (2018) | Other

  On star and biclique edge-colorings
  Dantas, S. and Groshaus, M. and Guedes, A. and Machado, R.C.S. and Ries, B. and Sasaki, D., International Transactions in Operational Research (2017) | Journal article

  Blocking independent sets for h -free graphs via edge contractions and vertex deletions
  Paulusma, D. and Picouleau, C. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2017) | Book

  Reducing the Chromatic Number by Vertex or Edge Deletions
  Picouleau, C. and Paulusma, D. and Ries, B., Electronic Notes in Discrete Mathematics (2017) | Journal article

  Contraction and deletion blockers for perfect graphs and h-free graphs?
  Diner, O.Y. and Paulusma, D. and Picouleau, C. and Ries, B. , arXiv (2017) | Other

  Critical Vertices and Edges in H-free Graphs^?
  Paulusma, D. and Picouleau, C. and Ries, B. , arXiv (2017) | Other

  Contraction and deletion blockers for perfect graphs and h-free graphs?
  Diner, O.Y. and Paulusma, D. and Picouleau, C. and Ries, B. , arXiv (2017) | Other

  Critical Vertices and Edges in H-free Graphs^?
  Paulusma, D. and Picouleau, C. and Ries, B. , arXiv (2017) | Other

  On the minimum and maximum selective graph coloring problems in some graph classes
  Demange, M. and Ekim, T. and Ries, B., Discrete Applied Mathematics (2016) | Journal article

  On the ratio between maximum weight perfect matchings and maximum weight matchings in grids
  Da Fonseca, G.D. and Ries, B. and Sasaki, D., Discrete Applied Mathematics (2016) | Journal article

  A boundary property for upper domination
  Aboueisha, H. and Hussain, S. and Lozin, V. and Monnot, J. and Ries, B. and Zamaraev, V. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2016) | Book

  Reducing the clique and chromatic number via edge contractions and vertex deletions
  Paulusma, D. and Picouleau, C. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2016) | Book

  Multiple referenda and multiwinner elections using Hamming distances: Complexity and manipulability
  Amanatidis, G. and Barrot, N. and Lang, J. and Markakis, E. and Ries, B., Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS: (2015) | Conference

  On some applications of the selective graph coloring problem
  Demange, M. and Ekim, T. and Ries, B. and Tanasescu, C., European Journal of Operational Research (2015) | Journal article

  Contraction blockers for graphs with forbidden induced paths
  Diner, Ö.Y. and Paulusma, D. and Picouleau, C. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2015) | Book

  Coloring graphs characterized by a forbidden subgraph
  Golovach, P.A. and Paulusma, D. and Ries, B., Discrete Applied Mathematics (2015) | Journal article

  On the bend number of circular-arc graphs as edge intersection graphs of paths on a grid
  Alcón, L. and Bonomo, F. and Durán, G. and Gutierrez, M. and Pía Mazzoleni, M. and Ries, B. and Valencia-Pabon, M., Electronic Notes in Discrete Mathematics (2015) | Journal article

  Finding a perfect phylogeny from mixed tumor samples
  Hujdurovié, A. and Kacar, U. and Milani?, M. and Ries, B. and Tomescu, A.I. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2015) | Book

  Approval voting for committee election: A general family of rules, their complexity and their manipulability,Vote par approbation pour les élections à vainqueurs multiples: Une famille générale de règles, leur complexité algorithmique et leur manipulabilité
  Barrot, N. and Lang, J. and Ries, B., Revue d’Intelligence Artificielle (2015) | Journal article

  On the maximum independent set problem in subclasses of subcubic graphs
  Lozin, V. and Monnot, J. and Ries, B., Journal of Discrete Algorithms (2015) | Journal article

  Blockers for the Stability Number and the Chromatic Number
  Bazgan, C. and Bentz, C. and Picouleau, C. and Ries, B., Graphs and Combinatorics (2015) | Journal article

  Advances in combinatorial optimization
  Martello, S. and Ries, B., Discrete Applied Mathematics (2015) | Journal article

  On the complexity of the selective graph coloring problem in some special classes of graphs?
  Demange, M. and Monnot, J. and Pop, P. and Ries, B., Theoretical Computer Science (2014) | Journal article

  A note on r-equitable k-colorings of trees
  Hertz, A. and Ries, B., Yugoslav Journal of Operations Research (2014) | Journal article

  A dichotomy for upper domination in monogenic classes
  Aboueisha, H. and Hussain, S. and Lozin, V. and Monnot, J. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2014) | Book

  Characterizations of cographs as intersection graphs of paths on a grid
  Cohen, E. and Golumbic, M.C. and Ries, B., Discrete Applied Mathematics (2014) | Journal article

  Perfectness of clustered graphs
  Bonomo, F. and Cornaz, D. and Ekim, T. and Ries, B., Discrete Optimization (2013) | Journal article

  GO VII Meeting, Ovronnaz (CH), June 13-17, 2010
  Demange, M. and Lozin, V. and Picouleau, C. and Ries, B., Discrete Applied Mathematics (2013) | Journal article

  Possible winners in approval voting
  Barrot, N. and Gourvès, L. and Lang, J. and Monnot, J. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013) | Book

  The firefighter problem with more than one firefighter on trees
  Bazgan, C. and Chopin, M. and Ries, B., Discrete Applied Mathematics (2013) | Journal article

  On the maximum independent set problem in subclasses of subcubic graphs
  Lozin, V. and Monnot, J. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013) | Book

  Optimal edge-coloring with edge rate constraints
  Dereniowski, D. and Kubiak, W. and Ries, B. and Zwols, Y., Networks (2013) | Journal article

  Packing and covering with linear programming: A survey
  Bentz, C. and Cornaz, D. and Ries, B., European Journal of Operational Research (2013) | Journal article

  On the Intersection Graphs of Orthogonal Line Segments in the Plane: Characterizations of Some Subclasses of Chordal Graphs
  Golumbic, M.C. and Ries, B., Graphs and Combinatorics (2013) | Journal article

  Coloring graphs characterized by a forbidden subgraph
  Golovach, P.A. and Paulusma, D. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012) | Book

  Some properties of edge intersection graphs of single-bend paths on a grid
  Asinowski, A. and Ries, B., Discrete Mathematics (2012) | Journal article

  Colouring vertices of triangle-free graphs without forests
  Dabrowski, K.K. and Lozin, V. and Raman, R. and Ries, B., Discrete Mathematics (2012) | Journal article

  A note on chromatic properties of threshold graphs
  Ries, B. and De Werra, D. and Zenklusen, R., Discrete Mathematics (2012) | Journal article

  Analyzing the performance of greedy maximal scheduling via local pooling and graph theory
  Birand, B. and Chudnovsky, M. and Ries, B. and Seymour, P. and Zussman, G. and Zwols, Y., IEEE/ACM Transactions on Networking (2012) | Journal article

  Selective graph coloring in some special classes of graphs
  Demange, M. and Monnot, J. and Pop, P. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012) | Book

  D-Transversals of stable sets and vertex covers in weighted bipartite graphs
  Bentz, C. and Costa, M.-C. and Picouleau, C. and Ries, B. and De Werra, D., Journal of Discrete Algorithms (2012) | Journal article

  Minimum d-Transversals of Maximum-Weight Stable Sets in Trees
  Bentz, C. and Costa, M.-C. and de Werra, D. and Picouleau, C. and Ries, B., Electronic Notes in Discrete Mathematics (2011) | Journal article

  A 2-approximation for the maximum satisfying bisection problem
  Ries, B. and Zenklusen, R., European Journal of Operational Research (2011) | Journal article

  Claw-free graphs with strongly perfect complements. Fractional and integral version, Part II: Nontrivial strip-structures
  Chudnovsky, M. and Ries, B. and Zwols, Y., Discrete Applied Mathematics (2011) | Journal article

  Claw-free graphs with strongly perfect complements. Fractional and integral version. Part I. Basic graphs
  Chudnovsky, M. and Ries, B. and Zwols, Y., Discrete Applied Mathematics (2011) | Journal article

  Split-critical and uniquely split-colorable graphs
  Ekim, T. and Ries, B. and De Werra, D., Discrete Mathematics and Theoretical Computer Science (2010) | Journal article

  Complexity of two coloring problems in cubic planar bipartite mixed graphs
  Ries, B., Discrete Applied Mathematics (2010) | Journal article

  Blockers and transversals in some subclasses of bipartite graphs: When caterpillars are dancing on a grid
  Ries, B. and Bentz, C. and Picouleau, C. and de Werra, D. and Costa, M.-C. and Zenklusen, R., Discrete Mathematics (2010) | Journal article

  Colouring vertices of triangle-free graphs
  Dabrowski, K. and Lozin, V. and Raman, R. and Ries, B. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2010) | Book

  On the use of graphs in discrete tomography
  de Werra, D. and Costa, M.-C. and Picouleau, C. and Ries, B., Annals of Operations Research (2010) | Journal article

  Analyzing the performance of greedy maximal scheduling via local pooling and graph theory
  Birand, B. and Chudnovsky, M. and Ries, B. and Seymour, P. and Zussman, G. and Zwols, Y., Proceedings - IEEE INFOCOM: (2010) | Conference

  Analyzing the performance of greedy maximal scheduling via local pooling and graph theory
  Birand, B. and Chudnovsky, M. and Ries, B. and Seymour, P. and Zussman, G. and Zwols, Y., Proceedings of the Annual International Conference on Mobile Computing and Networking, MOBICOM: (2010) | Conference

  Split-critical and uniquely split-colorable graphs
  Tınaz Ekim, Bernard Ries, Dominique De Werra, Discrete Mathematics & Theoretical Computer Science (2010) | Journal article

  Degree-constrained edge partitioning in graphs arising from discrete tomography
  Bentz, C. and Costa, M.-C. and Picouleau, C. and Ries, B. and de Werra, D., Journal of Graph Algorithms and Applications (2009) | Journal article

  Graph coloring with cardinality constraints on the neighborhoods
  Costa, M.-C. and de Werra, D. and Picouleau, C. and Ries, B., Discrete Optimization (2009) | Journal article

  Mixed graph edge coloring
  Furma?czyk, H. and Kosowski, A. and Ries, B. and Zyli?ski, P., Discrete Mathematics (2009) | Journal article

  Blockers and transversals
  Zenklusen, R. and Ries, B. and Picouleau, C. and de Werra, D. and Costa, M.-C. and Bentz, C., Discrete Mathematics (2009) | Journal article

  Some properties of edge intersection graphs of single bend paths on a grid
  Ries, B., Electronic Notes in Discrete Mathematics (2009) | Journal article

  On the use of graphs in discrete tomography
  De Werra, D. and Costa, M.-C. and Picouleau, C. and Ries, B., 4OR (2008) | Journal article

  On two coloring problems in mixed graphs
  Ries, B. and de Werra, D., European Journal of Combinatorics (2008) | Journal article

  Bicolored matchings in some classes of graphs (Graphs and Combinatorics (2007) 23, (47-60))
  Costa, M.C. and De Werra, D. and Picouleau, C. and Ries, B., Graphs and Combinatorics (2008) | Journal article

  On a graph coloring problem arising from discrete tomography
  Bentz, C. and Costa, M.C. and De Werra, D. and Picouleau, C. and Ries, B., Networks (2008) | Journal article

  Bicolored matchings in some classes of graphs
  Costa, M.C. and Werra, D.D. and Picouleau, C. and Ries, B., Graphs and Combinatorics (2007) | Journal article

  Coloring some classes of mixed graphs
  Ries, B., Discrete Applied Mathematics (2007) | Journal article

  Bicolored matchings in some classes of graphs
  Costa, M.-C. and de Werra, D. and Picouleau, C. and Ries, B., Electronic Notes in Discrete Mathematics (2005) | Journal article

• Research projects

  WG 2023
  Status: Completed

  Start	01.05.2023
  End	31.07.2023
  Funding	SNSF  Open project sheet
  WG conferences (Workshop on Graph-Theoretic Concepts in Computer Science) aim to connect theory and applications by demonstrating how graph-theoretic concepts can be applied in various areas of computer science. Organised in a different place each year, their goal is to present the strongest recent results and to identify and explore directions for future research. The Program Committee, composed of international experts in the field of theoretical computer science, decides on the accepted papers taking into account the reviews received for each submitted paper. A special issue of Springer's Lecture Notes in Computer Science will be published containing the accepted papers. The 49th edition of the International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2023) will be held at the University of Fribourg from June 28 to 30, 2023. It will be organised by the applicant together with Prof. Daniel Paulusma from Durham University (UK). Both will also chair the Program Committee. There will be three internationally-reknowned invited speakers: Prof. Flavia Bonomo, Dr. Eunjung Kim and Dr. Nicolas Trotignon.

  Efficient and sustainable waste collection
  Status: Completed

  Start	01.09.2019
  End	31.08.2022
  Funding	Innovation
  In Swiss municipalities, a curbside system is often used to collect the non-recoverable solid waste. In principle, the trucks stop at every household for the collection. Due to the many stops of the heavy trucks, this classic strategy causes high fuel consumption, emissions and noise. The objective of this project is to improve the municipal solid waste collection process by designing efficient and sustainable waste collection strategies targeted to the needs of the municipalities. This objective is pursued through the following three components. First, new waste collection concepts are proposed using modern physical waste collection elements, such as electric vehicles and containers with compressors. For example, small, agile vehicles may bring the garbage bags to larger containers in intermediate depots and large vehicles may then regularly discharge these containers. Second, mathematical models and optimization algorithms are developed for deciding how to design a waste collection concept for a given municipality in the best possible way. Typical decisions are about the locations of the waste collection points, the types of vehicles used to collect the waste at all collection points and the routing of each vehicle. Third, an interactive decision support tool is developed. It enables to specify the inputs, such as the street network and the waste quantities, and to display the results of the optimization algorithms for all alternatives. This tool will help the decision-makers to choose the best waste collection concept for their municipality.

Teaching and courses

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