Changing upper irredundance by edge addition

Upper domination and upper irredundance perfect graphs

Let β(G), Γ(G) and IR(G) be the independence number, the upper domination number and the upper irredundance number, respectively. A graph G is called Γperfect if β(H) = Γ(H), for every induced subgraph H of G. A graph G is called IR-perfect if Γ(H) = IR(H), for every induced subgraph H of G. In this paper, we present a characterization of Γ-perfect graphs in terms of some family of forbidden in...

Changing and unchanging acyclic domination: edge addition

Classes of Graphs for Which Upper Fractional Domination Equals Independence, Upper Domination, and upper Irredundance

This paper investigates cases where one graph parameter, upper fractional domination, is equal to three others: independence, upper domination and upper irredundance. We show that they are all equal for a large subclass, known as strongly perfect graphs, of the class of perfect graphs. They are also equal for odd cycles and upper bound graphs. However for simplicial graphs, upper irredundance m...

On Stability Number of Upper Irredundance Number in Graphs

A vertex v in a vertex-subset I of an undirected graph G is said to be redundant if its closed neighborhood is contained in the union of closed neighborhoods of vertices of I − {v}. In the context of a communication network , this means that any vertex that may receive communications from I may also be informed from I − {v} . The irredundance number ir(G) is the minimum cardinality taken over a...

The effect of the angle upper edge in shaped noise barriers with a T-shaped upper edge

Background and Objective: Efforts to improve the effectiveness of noise barriers have been made, including shape, aesthetics, form and gender. Therefore, the aim of this study was to investigate the effect of the angle upper edge in shaped noise barriers with a T-shaped upper edge. Materials and Methods: A 2D boundary element method (BEM) was used to predict the insertion loss of the tested ba...