The total interval number of an n-vertex graph with maximum degree β is at most (β+1/β)n/2, with equality if and only if every component of the graph is K β,β . If the graph is also required to be connected, then the maximum is βn/2 + 1 when β is even, but when β is odd it exceeds [β + 1/(2.5β + 7.7
Large P4-free graphs with bounded degree
β Scribed by Myung S. Chung; Douglas B. West
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 424 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0364-9024
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β¦ Synopsis
Abstract
Let ex * (D; H) denote the maximum number of edges in a connected graph with maximum degree D and no induced subgraph isomorphic to H. We prove that this is finite only when H is a disjoint union of paths,m in which case we provide crude upper and lower bounds. When H is the fourβvertex path P~4~, we prove that the complete bipartite graph K~D,D~ is the unique extremal graph. Furthermore, if G is a connected P~4~βfree graph with maximum degree D and clique number Ο, then G has at most D^2^ β D(Ο β 2)/2 edges. Β© 1993 John Wiley & Sons, Inc.
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