• b-Coloring Parameterized by Clique-Width 

      Jaffke, Lars; Lima, Paloma Thome de; Lokshtanov, Daniel (Journal article; Peer reviewed, 2021)
      We provide a polynomial-time algorithm for b-Coloring on graphs of constant clique-width. This unifies and extends nearly all previously known polynomial-time results on graph classes, and answers open questions posed by ...
    • A complexity dichotomy for critical values of the b-chromatic number of graphs 

      Lima, Paloma T.; Jaffke, Lars (Journal article; Peer reviewed, 2020)
      A b-coloring of a graph G is a proper coloring of its vertices such that each color class contains a vertex that has at least one neighbor in all the other color classes. The b-Coloring problem asks whether a graph G has ...
    • A complexity dichotomy for critical values of the b-chromatic number of graphs 

      Jaffke, Lars; Lima, Paloma T. (Peer reviewed; Journal article, 2019-08-20)
      A b-coloring of a graph G is a proper coloring of its vertices such that each color class contains a vertex that has at least one neighbor in all the other color classes. The b-Coloring problem asks whether a graph G has ...
    • Compressing permutation groups into grammars and polytopes. A graph embedding approach 

      Jaffke, Lars; De Oliveira Oliveira, Mateus; Tiwary, Hans Raj (Journal article; Peer reviewed, 2020)
      It can be shown that each permutation group G ⊑ 𝕊_n can be embedded, in a well defined sense, in a connected graph with O(n+|G|) vertices. Some groups, however, require much fewer vertices. For instance, 𝕊_n itself can ...
    • Diverse Pairs of Matchings 

      Fomin, Fedor; Golovach, Petr; Jaffke, Lars; Philip, Geevarghese; Sagunov, Danil (Journal article; Peer reviewed, 2020)
      We initiate the study of the Diverse Pair of (Maximum/ Perfect) Matchings problems which given a graph G and an integer k, ask whether G has two (maximum/perfect) matchings whose symmetric difference is at least k. Diverse ...
    • FPT Algorithms for Diverse Collections of Hitting Sets 

      Baste, Julien; Jaffke, Lars; Masařík, Tomáš; Philip, Geevarghese; Rote, Günter (Peer reviewed; Journal article, 2019-11-27)
      In this work, we study the d-Hitting Set and Feedback Vertex Set problems through the paradigm of finding diverse collections of r solutions of size at most k each, which has recently been introduced to the field of ...
    • Mim-Width II. The Feedback Vertex Set Problem 

      Jaffke, Lars; Kwon, O-Joung; Telle, Jan Arne (Peer reviewed; Journal article, 2020)
      We give a first polynomial-time algorithm for (WEIGHTED) FEEDBACK VERTEX SET on graphs of bounded maximum induced matching width (mim-width). Explicitly, given a branch decomposition of mim-width w, we give an nO(w)-time ...
    • Mim-Width III. Graph powers and generalized distance domination problems 

      Telle, Jan Arne; Jaffke, Lars; Strømme, Torstein Jarl Fagerbakke; Kwon, O-Joung (Peer reviewed; Journal article, 2019)
      We generalize the family of (σ,ρ) problems and locally checkable vertex partition problems to their distance versions, which naturally captures well-known problems such as Distance-r Dominating Set and Distance-r Independent ...
    • Structural parameterizations of clique coloring 

      Jaffke, Lars; Lima, Paloma T.; Philip, Geevarghese (Journal article; Peer reviewed, 2020)
      A clique coloring of a graph is an assignment of colors to its vertices such that no maximal clique is monochromatic. We initiate the study of structural parameterizations of the Clique Coloring problem which asks whether ...
    • Three problems on well-partitioned chordal graphs 

      Ahn, Jungho; Jaffke, Lars; Kwon, O-Joung; Lima, Paloma Thome de (Journal article; Peer reviewed, 2021)
      In this work, we solve three problems on well-partitioned chordal graphs. First, we show that every connected (resp., 2-connected) well-partitioned chordal graph has a vertex that intersects all longest paths (resp., longest ...
    • Typical Sequences Revisited - Computing Width Parameters of Graphs 

      Bodlaender, Hans L.; Jaffke, Lars; Telle, Jan Arne (Journal article; Peer reviewed, 2021)
      In this work, we give a structural lemma on merges of typical sequences, a notion that was introduced in 1991 [Lagergren and Arnborg, Bodlaender and Kloks, both ICALP 1991] to obtain constructive linear time parameterized ...
    • Typical Sequences Revisited – Computing Width Parameters of Graphs 

      Bodlaender, Hans L.; Jaffke, Lars; Telle, Jan Arne (Journal article; Peer reviewed, 2020)
      In this work, we give a structural lemma on merges of typical sequences, a notion that was introduced in 1991 [Lagergren and Arnborg, Bodlaender and Kloks, both ICALP 1991] to obtain constructive linear time parameterized ...
    • What Is Known About Vertex Cover Kernelization? 

      Fellows, Michael R.; Jaffke, Lars; Király, Aliz Izabella; Rosamond, Frances; Weller, Mathias (Peer reviewed; Journal article, 2018)
      We are pleased to dedicate this survey on kernelization of the Vertex Cover problem, to Professor Juraj Hromkovič on the occasion of his 60th birthday. The Vertex Cover problem is often referred to as the Drosophila of ...