A graph G is pluperfect if one can add new multiple edges to obtain a multi graph M satisfying: (1) G spans M, (2) the degrees of the nodes of M are consecutive integers, (3) G and M have the same minimum degree. Our purpose is to display several families of pluperfect graphs in order to L Introduction My good friends Mehdi Behzad and Gary Chartrand wrote a note [1] titled "No graph is perfect"...

A removahedron is a polytope obtained by deleting inequalities from the facet description of the classical permutahedron. Relevant examples range from the associahedra to the permutahedron itself, which raises the natural question to characterize which nestohedra can be realized as removahedra. In this note, we show that the nested complex of any connected building set closed under intersection...

A digraph D is round if the vertices of D can be circularly ordered as VI, V2, ... , Vn so that, for each vertex Vi, the out-neighbours of Vi appear consecutively following Vi and the in-neighbours of Vi appear consecutively preceding Vi in the ordering. We characterize round digraphs in terms of forbidden substructures. Our proof implies a polynomial algorithm to decide if a digraph is round.

The traditional setup of link prediction in networks assumes that a test set node pairs, which is usually balanced, available over to predict the presence links. However, practice, there no set: ground truth not known, so number possible pairs quadratic nodes graph. Moreover, because graphs are sparse, most these will be Thus, methods, often rely on proximity-preserving embeddings or heuristic ...

Comparative Study of the Way in Which Teachers are Assigned to Schools Abroad R. Kachoueian Javaadi, Ph.D.* B. Shaahtaalebi, Ph.D.** M.A. Naadi, Ph.D.***   To find ways of improving the way in which Iranian teachers are assigned to schools abroad, a comparative study was conducted in order to look at way this task is done in the U.S., France, Germany, Canada, England, Russia, Aust...