Results 31 to 40 of about 2,549 (154)

On edge-intersection graphs of k-bend paths in grids [PDF]

Discrete Mathematics & Theoretical Computer Science, 2010
Edge-intersection graphs of paths in grids are graphs that can be represented such that vertices are paths in a grid and edges between vertices of the graph exist whenever two grid paths share a grid edge. This type of graphs is motivated by applications
Therese Biedl, Michal Stern
doaj   +1 more source

Obstructions to within a few vertices or edges of acyclic [PDF]

, 1995
Finite obstruction sets for lower ideals in the minor order are guaranteed to exist by the Graph Minor Theorem. It has been known for several years that, in principle, obstruction sets can be mechanically computed for most natural lower ideals.
Cattell, Kevin, Dinneen, Michael J., Fellows, Michael R.   +2 more
core   +3 more sources

On the Pathwidth of Almost Semicomplete Digraphs [PDF]

, 2015
We call a digraph {\em $h$-semicomplete} if each vertex of the digraph has at most $h$ non-neighbors, where a non-neighbor of a vertex $v$ is a vertex $u \neq v$ such that there is no edge between $u$ and $v$ in either direction. This notion generalizes that of semicomplete digraphs which are $0$-semicomplete and tournaments which are semicomplete and ...
Kitsunai, Kenta, Kobayashi, Yasuaki, Tamaki, Hisao   +2 more
openaire   +2 more sources

Pagenumber of pathwidth-k graphs and strong pathwidth-k graphs

Discrete Mathematics, 2002
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Togasaki, Mitsunori, Yamazaki, Koichi
openaire   +1 more source

The Pebble-Relation Comonad in Finite Model Theory [PDF]

Logical Methods in Computer Science
The pebbling comonad, introduced by Abramsky, Dawar and Wang, provides a categorical interpretation for the k-pebble games from finite model theory.
Yoàv Montacute, Nihil Shah
doaj   +1 more source

Solving Vertex Cover in Polynomial Time on Hyperbolic Random Graphs [PDF]

, 2020
The VertexCover problem is proven to be computationally hard in different ways: It is NP-complete to find an optimal solution and even NP-hard to find an approximation with reasonable factors.
, Fischbeck, Philipp, Friedrich, Tobias, Katzmann, Maximilian   +3 more
core   +3 more sources

EPG-representations with small grid-size [PDF]

, 2017
In an EPG-representation of a graph $G$ each vertex is represented by a path in the rectangular grid, and $(v,w)$ is an edge in $G$ if and only if the paths representing $v$ an $w$ share a grid-edge. Requiring paths representing edges to be x-monotone or,
A Asinowski, D Epstein, D Heldt, H Bodlaender, I Markov, M Francis, M Golumbic, M Grohe, MC Golumbic, MJ Alam, R Diestel, T Biedl   +11 more
core   +2 more sources

Semantic Tree-Width and Path-Width of Conjunctive Regular Path Queries [PDF]

Logical Methods in Computer Science
We show that the problem of whether a query is equivalent to a query of tree-width $k$ is decidable, for the class of Unions of Conjunctive Regular Path Queries with two-way navigation (UC2RPQs).
Diego Figueira, Rémi Morvan
doaj   +1 more source

Superpatterns and Universal Point Sets [PDF]

, 2013
An old open problem in graph drawing asks for the size of a universal point set, a set of points that can be used as vertices for straight-line drawings of all n-vertex planar graphs.
A. Marcus, A. Miller, B. Bukh, D. Dolev, D. Eppstein, D. Eppstein, D. Rotem, H. Eriksson, H. Fraysseix de, M. Chrobak, M. Kurowski, P. Angelini, P. Gritzmann, R. Fulek, S. Bereg   +14 more
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The Firefighter Problem: A Structural Analysis [PDF]

, 2014
We consider the complexity of the firefighter problem where b>=1 firefighters are available at each time step. This problem is proved NP-complete even on trees of degree at most three and budget one (Finbow et al.,2007) and on trees of bounded degree b+3
A King, B Hartnell, C Bazgan, C Bazgan, E Anshelevich, E Korach, FV Fomin, G MacGillivray, HL Bodlaender, KL Ng, L Cai, M Develin, M Doucha, MR Garey, S Finbow, V Costa, Y Iwaikawa   +16 more
core   +3 more sources