ARSCOM
2008
13 years 2 months ago
2008
A total perfect code in a graph is a subset of the graph's vertices with the property that each vertex in the graph is adjacent to exactly one vertex in the subset. We prove t...
ARSCOM
2008
13 years 4 months ago
2008
ARSCOM
2008
13 years 4 months ago
2008
ARSCOM
2008
13 years 4 months ago
2008
The eccentricity e(v) of a vertex v in a strongly connected digraph G is the maximum distance from v. The eccentricity sequence of a digraph is the list of eccentricities of its v...
ARSCOM
2008
13 years 4 months ago
2008
Various enumeration problems for classes of simply generated families of trees have been the object of investigation in the past. We mention the enumeration of independent subsets,...
ARSCOM
2008
13 years 4 months ago
2008
ARSCOM
2008
13 years 4 months ago
2008
We classify the minimal blocking sets of size 15 in PG(2, 9). We show that the only examples are the projective triangle and the sporadic example arising from the secants to the u...
ARSCOM
2008
13 years 4 months ago
2008
We present 3 open challenges in the field of Costas arrays. They are: a) the determination of the number of dots on the main diagonal of a Welch array, and especially the maximal ...
ARSCOM
2008
13 years 4 months ago
2008
We prove the non-existence of maximal partial spreads of size 76 in PG(3, 9). Relying on the classification of the minimal blocking sets of size 15 in PG(2, 9) [22], we show that ...
ARSCOM
2008
13 years 4 months ago
2008
A (k; g)-graph is a k-regular graph with girth g. A (k; g)-cage is a (k; g)-graph with the least number of vertices. In this note, we show that (k; g)-cage has an r-factor of girt...