## Abstract A matrix with positive row sums and all its offβdiagonal elements bounded above by their corresponding row averages is called a __B__βmatrix by J. M. PeΓ±a in References (__SIAM J. Matrix Anal. Appl.__ 2001; **22**:1027β1037) and (__Numer. Math.__ 2003; **95**:337β345). In this paper, it
On some subclasses of well-covered graphs
β Scribed by Jo Ann W. Staples
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- English
- Weight
- 367 KB
- Volume
- 3
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
A set of points in a graph is independent if no two points in the set are adjacent. A graph is well covered if every maximal independent set is a maximum independent set or, equivalently, if every independent set is contained in a maximum independent set. The well-covered graphs are classified by the W,, property: For a positive integer n, a graph G belongs to class W,, if \ V ( G ) I r n and any n disjoint independent sets are contained in n disjoint maximum independent sets. Constructions are presented that show how to build infinite families of W,, graphs containing arbitrarily large independent sets. A characterization of W, graphs in terms of well-covered subgraphs is given, a s well a s bounds for the size of a maximum independent set and the minimum and maximum degrees of points in W, graphs.
π SIMILAR VOLUMES
The class of Z m -well-covered graphs, those in which the cardinality of every maximal independent subset of vertices is congruent to the same number modulo m, contains the well-covered graphs as well as parity graphs. Here we consider such graphs, where there is no small cycle present and obtain a
A graph is well-covered if all its maximal independent sets are of the same cardinality. Deciding whether a given graph is well-covered is known to be NP-hard in general, and solvable in polynomial time, if the input is restricted to certain families of graphs. We present here a simple structural ch
## Abstract A graph is well covered if every maximal independent set has the same cardinality. A vertex __x__, in a wellβcovered graph __G__, is called extendable if __G β {x}__ is well covered and Ξ²(__G__) = Ξ²(__G β {x}__). If __G__ is a connected, wellβcovered graph containing no 4β nor 5βcycles