The search session has expired. Please query the service again.

The search session has expired. Please query the service again.

The search session has expired. Please query the service again.

The search session has expired. Please query the service again.

Displaying similar documents to “Digraphs with isomorphic underlying and domination graphs: connected U G c ( d ) ”

Two classes of graphs related to extremal eccentricities

Ferdinand Gliviak (1997)

Mathematica Bohemica

Similarity:

A graph G is called an S -graph if its periphery P e r i ( G ) is equal to its center eccentric vertices C e p ( G ) . Further, a graph G is called a D -graph if P e r i ( G ) ∩ C e p ( G ) = ∅ . We describe S -graphs and D -graphs for small radius. Then, for a given graph H and natural numbers r ≥ 2 , n ≥ 2 , we construct an S -graph of radius r having n central vertices and containing H as an induced subgraph. We prove an analogous existence theorem for D -graphs, too. At the end, we give some properties of S -graphs and D -graphs.

On infinite uniquely partitionable graphs and graph properties of finite character

Jozef Bucko, Peter Mihók (2009)

Discussiones Mathematicae Graph Theory

Similarity:

A graph property is any nonempty isomorphism-closed class of simple (finite or infinite) graphs. A graph property is of finite character if a graph G has a property if and only if every finite induced subgraph of G has a property . Let ₁,₂,...,ₙ be graph properties of finite character, a graph G is said to be (uniquely) (₁, ₂, ...,ₙ)-partitionable if there is an (exactly one) partition V₁, V₂, ..., Vₙ of V(G) such that G [ V i ] ∈ i for i = 1,2,...,n. Let us denote by ℜ = ₁ ∘ ₂ ∘ ... ∘ ₙ the class...

On well-covered graphs of odd girth 7 or greater

Bert Randerath, Preben Dahl Vestergaard (2002)

Discussiones Mathematicae Graph Theory

Similarity:

A maximum independent set of vertices in a graph is a set of pairwise nonadjacent vertices of largest cardinality α. Plummer [14] defined a graph to be well-covered, if every independent set is contained in a maximum independent set of G. One of the most challenging problems in this area, posed in the survey of Plummer [15], is to find a good characterization of well-covered graphs of girth 4. We examine several subclasses of well-covered graphs of girth ≥ 4 with respect to the odd girth...

Cores and shells of graphs

Allan Bickle (2013)

Mathematica Bohemica

Similarity:

The k -core of a graph G , C k ( G ) , is the maximal induced subgraph H ⊆ G such that δ ( G ) ≥ k , if it exists. For k > 0 , the k -shell of a graph G is the subgraph of G induced by the edges contained in the k -core and not contained in the ( k + 1 ) -core. The core number of a vertex is the largest value for k such that v ∈ C k ( G ) , and the maximum core number of a graph, C ^ ( G ) , is the maximum of the core numbers of the vertices of G . A graph G is k -monocore if C ^ ( G ) = δ ( G ) = k . This paper discusses some basic results on the structure of k -cores and...

Graphs with the same peripheral and center eccentric vertices

Peter Kyš (2000)

Mathematica Bohemica

Similarity:

The eccentricity e ( v ) of a vertex v is the distance from v to a vertex farthest from v , and u is an eccentric vertex for v if its distance from v is d ( u , v ) = e ( v ) . A vertex of maximum eccentricity in a graph G is called peripheral, and the set of all such vertices is the peripherian, denoted P e r i G ) . We use C e p ( G ) to denote the set of eccentric vertices of vertices in C ( G ) . A graph G is called an S-graph if C e p ( G ) = P e r i ( G ) . In this paper we characterize S-graphs with diameters less or equal to four, give some constructions of...