Let G be a connected graph with p vertices and n a positive integer with 1 dn <(p/2) -1. G is said to be O-extendable if G has a perfect matching. G is said to be n-extendable if G has a matching of size n and every matching of size n in G extends to (i.e. is a subset of) a perfect matching. It is s
A local independence number condition for n-extendable graphs
β Scribed by Dingjun Lou
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 273 KB
- Volume
- 195
- Category
- Article
- ISSN
- 0012-365X
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β¦ Synopsis
Let G be a graph and v C V(G). Let Nk(v)= {ulu C V(G) and d(u, v)= k}. It is proved that if G is a connected graph with oo>9(G)~>4 and with even order and if, for each vertex
is regular and rd(v)/4]-extendable. All results in this paper are sharp. (~) 1999 Elsevier Science B.V. All rights reserved Keywords." Local condition; Independence number; n-extendable graph All graphs considered are finite, undirected and simple.
Let n be a positive integer and G be a graph with v>~2n + 2. G is said to be n-extendable if G has n independent edges and any n independent edges of G are contained in a perfect matching of G.
Let G be a graph and vE V(G). Let Nk
and H be a subgraph of G. Then we use the notation Ns(v)=N(v)NS and NH(v)=N(v)N V(H). And ds(v)= INs(v)[ and dH(V)= [NH(v)[. Let x be a real number. We denote by r x] the least integer m such that m>>,x and by Ix] the largest integer m such that m ~x.
For the terminology and notation not defined in this paper, the reader is referred to [3].
π SIMILAR VOLUMES
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Let G = (V, E ) be a graph on n vertices with average degree t 2 1 in which for every vertex u E V the induced subgraph on the set of all neighbors of u is r-colorable. We show that the independence number of G is at least log t , for some absolute positive constant c. This strengthens a well-known
## Abstract Let __G__ be a graph and __f__ be a mapping from __V__(__G__) to the positive integers. A subgraph __T__ of __G__ is called an __f__βtree if __T__ forms a tree and __d__~__T__~(__x__)β€__f__(__x__) for any __x__β__V__(__T__). We propose a conjecture on the existence of a spanning __f__βt