A generating function for fatgraphs
In this paper, a new kind of graph on a commutative ring is introduced and investigated. Small intersection graph of a ring , denoted by , is a graph with all non-small proper ideals of as vertices and two distinct vertices and are adjacent if and only if is not small in . In this article, some interrelation between the graph theoretic properties of this graph and some algebraic properties of rings are studied. We investigated the basic properties of the small intersection graph as diameter,...
Assessing the number of clusters of a statistical population is one of the essential issues of unsupervised learning. Given n independent observations X1,...,Xn drawn from an unknown multivariate probability density f, we propose a new approach to estimate the number of connected components, or clusters, of the t-level set . The basic idea is to form a rough skeleton of the set using any preliminary estimator of f, and to count the number of connected components of the resulting graph. Under...
The split graph on vertices is denoted by . A non-increasing sequence of nonnegative integers is said to be potentially -graphic if there exists a realization of containing as a subgraph. In this paper, we obtain a Havel-Hakimi type procedure and a simple sufficient condition for to be potentially -graphic. They are extensions of two theorems due to A. R. Rao (The clique number of a graph with given degree sequence, Graph Theory, Proc. Symp., Calcutta 1976, ISI Lect. Notes Series...