3471 search results - page 26 / 695 » Obstacle Numbers of Graphs |
CORR
2006
Springer
13 years 8 months ago
2006
Springer
We show that the number of k-matching in a given undirected graph G is equal to the number of perfect matching of the corresponding graph Gk on an even number of vertices divided ...
MLQ
2011
13 years 2 months ago
2011
Given a graph G whose set of vertices is a Polish space X, the weak Borel chromatic number of G is the least size of a family of pairwise disjoint G-independent Borel sets that cov...
JGT
2006
13 years 7 months ago
2006
Given a configuration of pebbles on the vertices of a graph G, a pebbling move consists of taking two pebbles off some vertex v and putting one of them back on a vertex adjacent t...
FCT
2009
Springer
14 years 2 months ago
2009
Springer
We study the empire colouring problem (as defined by Percy Heawood in 1890) for maps whose dual planar graph is a tree, with empires formed by exactly r countries. We prove that, ...
DM
2008
13 years 8 months ago
2008
The reinforcement number of a graph is the smallest number of edges that have to be added to a graph to reduce the domination number. We introduce the k-reinforcement number of a ...