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Stationary map coloring

Omer Angel, Itai Benjamini, Ori Gurel-Gurevich, Tom Meyerovitch, Ron Peled (2012)

Annales de l'I.H.P. Probabilités et statistiques

We consider a planar Poisson process and its associated Voronoi map. We show that there is a proper coloring with 6 colors of the map which is a deterministic isometry-equivariant function of the Poisson process. As part of the proof we show that the 6-core of the corresponding Delaunay triangulation is empty. Generalizations, extensions and some open questions are discussed.

Statuses and branch-weights of weighted trees

Chiang Lin, Jen-Ling Shang (2009)

Czechoslovak Mathematical Journal

In this paper we show that in a tree with vertex weights the vertices with the second smallest status and those with the second smallest branch-weight are the same.

Statuses and double branch weights of quadrangular outerplanar graphs

Halina Bielak, Kamil Powroźnik (2015)

Annales UMCS, Mathematica

In this paper we study some distance properties of outerplanar graphs with the Hamiltonian cycle whose all bounded faces are cycles isomorphic to the cycle C4. We call this family of graphs quadrangular outerplanar graphs. We give the lower and upper bound on the double branch weight and the status for this graphs. At the end of this paper we show some relations between median and double centroid in quadrangular outerplanar graphs

Stopping Markov processes and first path on graphs

Giacomo Aletti, Ely Merzbach (2006)

Journal of the European Mathematical Society

Given a strongly stationary Markov chain (discrete or continuous) and a finite set of stopping rules, we show a noncombinatorial method to compute the law of stopping. Several examples are presented. The problem of embedding a graph into a larger but minimal graph under some constraints is studied. Given a connected graph, we show a noncombinatorial manner to compute the law of a first given path among a set of stopping paths.We prove the existence of a minimal Markov chain without oversized information....

Stratidistance in stratified graphs

Gary Chartrand, Heather Gavlas, Michael A. Henning, Reza Rashidi (1997)

Mathematica Bohemica

A graph G is a stratified graph if its vertex set is partitioned into classes (each of which is a stratum or a color class). A stratified graph with k strata is k -stratified. If G is a connected k -stratified graph with strata S i ( 1 i ...

Strong asymmetric digraphs with prescribed interior and annulus

Steven J. Winters (2001)

Czechoslovak Mathematical Journal

The directed distance d ( u , v ) from u to v in a strong digraph D is the length of a shortest u - v path in D . The eccentricity e ( v ) of a vertex v in D is the directed distance from v to a vertex furthest from v in D . The center and periphery of a strong digraph are two well known subdigraphs induced by those vertices of minimum and maximum eccentricities, respectively. We introduce the interior and annulus of a digraph which are two induced subdigraphs involving the remaining vertices. Several results concerning...

Strong Chromatic Index Of Planar Graphs With Large Girth

Gerard Jennhwa Chang, Mickael Montassier, Arnaud Pêche, André Raspaud (2014)

Discussiones Mathematicae Graph Theory

Let Δ ≥ 4 be an integer. In this note, we prove that every planar graph with maximum degree Δ and girth at least 1 Δ+46 is strong (2Δ−1)-edgecolorable, that is best possible (in terms of number of colors) as soon as G contains two adjacent vertices of degree Δ. This improves [6] when Δ ≥ 6.

Strong Equality Between the Roman Domination and Independent Roman Domination Numbers in Trees

Mustapha Chellali, Nader Jafari Rad (2013)

Discussiones Mathematicae Graph Theory

A Roman dominating function (RDF) on a graph G = (V,E) is a function f : V −→ {0, 1, 2} satisfying the condition that every vertex u for which f(u) = 0 is adjacent to at least one vertex v for which f(v) = 2. The weight of an RDF is the value f(V (G)) = P u2V (G) f(u). An RDF f in a graph G is independent if no two vertices assigned positive values are adjacent. The Roman domination number R(G) (respectively, the independent Roman domination number iR(G)) is the minimum weight of an RDF (respectively,...

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