The -step competition graphs of doubly partial orders
โ Scribed by Boram Park; Jung Yeun Lee; Suh-Ryung Kim
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 239 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0893-9659
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โฆ Synopsis
The competition graph of a doubly partial order is an interval graph. The competitioncommon enemy graph, a variant of the competition graph, of a doubly partial order is also an interval graph if it does not contain a 4-cycle as an induced subgraph. It is natural to ask whether or not the same phenomenon occurs for other interesting variants of the competition graph. In this paper, we study the m-step competition graph, a generalization of the competition graph, of a doubly partial order. We show that the m-step competition graph of a doubly partial order is an interval graph for every positive integer m. We also show that given a positive integer m, an interval graph with sufficiently many isolated vertices is the m-step competition graph of a doubly partial order.
๐ SIMILAR VOLUMES
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It is known to be a hard problem to compute the competition number k(G) of a graph G in general. Park and Sano (in press) [16] gave the exact values of the competition numbers of Hamming graphs H(n, q) if 1 โค n โค 3 or 1 โค q โค 2. In this paper, we give an explicit formula for the competition numbers
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If P and Q are partial orders, then the dimension of the cartesian product P x Q does not exceed the sum of the dimensions of P and Q. There are several known sufficient conditions for this bound to be attained, on the other hand, the only known lower bound for the dimension of a cartesian product i