From Pathwidth to Connected Pathwidth

Dariusz Dereniowski (1)

1 Gdansk University of Technology - Department of Algorithms and Systems Modelling [ETI GUT]

It is proven that the connected pathwidth of any graph $G$ is at most $2\cdot\pw(G)+1$, where $\pw(G)$ is the pathwidth of $G$. The method is constructive, i.e. it yields an efficient algorithm that for a given path decomposition of width $k$ computes a connected path decomposition of width at most $2k+1$. The running time of the algorithm is $O(dk^2)$, where $d$ is the number of `bags' in the input path decomposition. The motivation for studying connected path decompositions comes from the connection between the pathwidth and some graph searching games. One of the advantages of the above bound for connected pathwidth is an inequality $\csn(G)\leq 2\sn(G)+3$, where $\csn(G)$ is the connected search number of a graph $G$ and $\sn(G)$ is its search number, which holds for any graph $G$. Moreover, the algorithm presented in this work can be used to convert efficiently a given search strategy using $k$ searchers into a connected one using $2k+3$ searchers and starting at arbitrary homebase.

Mots clés: connected pathwidth; connected searching; fugitive search games; graph searching; pathwidth

Domaines: Complexité [cs.CC]; Algorithme et structure de données [cs.DS]

Dariusz Dereniowski. From Pathwidth to Connected Pathwidth. Symposium on Theoretical Aspects of Computer Science (STACS2011), Mar 2011, Dortmund, Germany. pp.416-427. ⟨hal-00573616⟩