8 citations · 15 across the 4 of their papers we have counts for
9 papers
W[1]-Hardness of Upper Clique Transversal
J. Pascal Gollin, Pascal J. Gollin, Tesshu Hanaka +3
A clique transversal of a graph is a set of vertices intersecting every maximal clique. We prove that deciding whether a graph has an inclusion-wise minimal clique transversal of s…
On Kernels and Leaves: Searching for Bare and Lush Trees
Jesse Beisegel, Ekkehard Köhler, Robert Scheffler +1
We study a variation of the classical Maximum (Minimum) Leaf Spanning Tree problem. In many applications, Depth-First Search (DFS) is used to compute a spanning tree of a graph. Su…
Sandwich Monotonicity and Recognition of Weighted Graph Classes
Jesse Beisegel, Nina Chiarelli, Ekkehard Köhler +5
Edge-weighted graphs play an important role in the theory of Robinsonian matrices and similarity theory, particularly via the concept of level graphs, that is, graphs obtained from…
The Simultaneous Interval Number: A New Width Parameter that Measures the Similarity to Interval Graphs
Jesse Beisegel, Nina Chiarelli, Ekkehard Köhler +3
We propose a novel way of generalizing the class of interval graphs, via a graph width parameter called the simultaneous interval number. This parameter is related to the simultane…
Graph Search Trees and the Intermezzo Problem
Jesse Beisegel, Ekkehard Köhler, Fabienne Ratajczak +2
The last in-tree recognition problem asks whether a given spanning tree can be derived by connecting each vertex with its rightmost left neighbor of some search ordering. In this s…
On the End-Vertex Problem of Graph Searches
Jesse Beisegel, Carolin Denkert, Ekkehard Köhler +4
End vertices of graph searches can exhibit strong structural properties and are crucial for many graph algorithms. The problem of deciding whether a given vertex of a graph is an e…
Traffic signal optimization: combining static and dynamic models
Ekkehard Köhler, Martin Strehler
In this paper, we present a cyclically time-expanded network model for simultaneous optimization of traffic assignment and traffic signal parameters, in particular offsets, split t…
Line-distortion, Bandwidth and Path-length of a graph
Feodor F. Dragan, Ekkehard Köhler, Arne Leitert
We investigate the minimum line-distortion and the minimum bandwidth problems on unweighted graphs and their relations with the minimum length of a Robertson-Seymour's path-decompo…
Linear Time LexDFS on Cocomparability Graphs
Ekkehard Köhler, Lalla Mouatadid
Lexicographic depth first search (LexDFS) is a graph search protocol which has already proved to be a powerful tool on cocomparability graphs. Cocomparability graphs have been well…