Fully polynomial FPT algorithms for some classes of bounded clique-width graphs

D Coudert, G Ducoffe, A Popa - ACM Transactions on Algorithms (TALG), 2019 - dl.acm.org
Recently, hardness results for problems in P were achieved using reasonable complexity-
theoretic assumptions such as the Strong Exponential Time Hypothesis. According to these …

Finding four-node subgraphs in triangle time

VV Williams, JR Wang, R Williams, H Yu - … of the twenty-sixth annual ACM …, 2014 - SIAM
We present new algorithms for finding induced four-node subgraphs in a given graph, which
run in time roughly that of detecting a clique on three nodes (ie, a triangle). The best known …

[HTML][HTML] Applying clique-decomposition for computing Gromov hyperbolicity

N Cohen, D Coudert, G Ducoffe, A Lancin - Theoretical computer science, 2017 - Elsevier
Given a graph, its hyperbolicity is a measure of how close its distance distribution is to the
one of a tree. This parameter has gained recent attention in the analysis of some graph …

-Metric Graphs: Hyperbolicity

FF Dragan, G Ducoffe - arXiv preprint arXiv:2404.14792, 2024 - arxiv.org
A graph is called $\alpha_i $-metric ($ i\in {\cal N} $) if it satisfies the following $\alpha_i $-
metric property for every vertices $ u, w, v $ and $ x $: if a shortest path between $ u $ and …

On computing the Gromov hyperbolicity

N Cohen, D Coudert, A Lancin - Journal of Experimental Algorithmics …, 2015 - dl.acm.org
The Gromov hyperbolicity is an important parameter for analyzing complex networks which
expresses how the metric structure of a network looks like a tree. It is for instance used to …

Fast approximation and exact computation of negative curvature parameters of graphs

J Chalopin, V Chepoi, FF Dragan, G Ducoffe… - Discrete & …, 2021 - Springer
In this paper, we study Gromov hyperbolicity and related parameters, that represent how
close (locally) a metric space is to a tree from a metric point of view. The study of Gromov …

Fast deterministic algorithms for computing all eccentricities in (hyperbolic) Helly graphs

FF Dragan, G Ducoffe, HM Guarnera - Journal of Computer and System …, 2025 - Elsevier
A graph is Helly if every family of pairwise intersecting balls has a nonempty common
intersection. The class of Helly graphs is the discrete analogue of the class of hyperconvex …

When can graph hyperbolicity be computed in linear time?

T Fluschnik, C Komusiewicz, GB Mertzios, A Nichterlein… - Algorithmica, 2019 - Springer
Hyperbolicity is a distance-based measure of how close a given graph is to being a tree.
Due to its relevance in modeling real-world networks, hyperbolicity has seen intensive …

[HTML][HTML] On the hyperbolicity of bipartite graphs and intersection graphs

D Coudert, G Ducoffe - Discrete Applied Mathematics, 2016 - Elsevier
Hyperbolicity is a measure of the tree-likeness of a graph from a metric perspective.
Recently, it has been used to classify complex networks depending on their underlying …

[HTML][HTML] Obstructions to a small hyperbolicity in Helly graphs

FF Dragan, HM Guarnera - Discrete Mathematics, 2019 - Elsevier
The δ-hyperbolicity of a graph is defined by a simple 4-point condition: for any four vertices
u, v, w, and x, the two larger of the distance sums d (u, v)+ d (w, x), d (u, w)+ d (v, x), and d (u …