Let ⌫ be a distance-regular graph with l (1 , a 1 , b 1 ) ϭ 1 and c s ϩ 1 ϭ 1 for some positive integer s . We show the existence of a certain distance-regular graph of diameter s , containing given two vertices at distance s , as a subgraph in ⌫ .
Subgraph distances in graphs defined by edge transfers
✍ Scribed by Gary Chartrand; Héctor Hevia; Elzbieta B. Jarrett; Michelle Schultz
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 800 KB
- Volume
- 170
- Category
- Article
- ISSN
- 0012-365X
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✦ Synopsis
For two edge-induced subgraphs F and H of the same size in a graph G, the subgraph H can be obtained from F by an edge jump if there exist four distinct vertices u, v, w, and x in G such that uv ~ E(F), wx ~ E(G) -E(F), and H = F -uv + wx. The subgraph F is j-transformed into H ifH can be obtained from F by a sequence of edge jumps. Necessary and sufficient conditions are presented for a graph G to have the property that every edge-induced subgraph of a fixed size in G can be j-transformed into every other edge-induced subgraph of that size. The minimum number of edge jumps required to transform one subgraph into another is called the jump distance. This distance is a metric and can be modeled by a graph. The jump graph J(G) of a graph G is defined as that graph whose vertices are the edges of G and where two vertices of J (G) are adjacent if and only if the corresponding edges of G are independent. For a given graph G, we consider the sequence {Jk(G)} of iterated jump graphs and classify each graph as having a convergent, divergent, or terminating sequence.
📜 SIMILAR VOLUMES
Let ⌫ be a distance-regular graph with a 1 Ͼ 0 , r ϭ max ͕ j 3 ( c j , a j , b j ) ϭ ( c 1 , a 1 , b 1 ) ͖ у 2 and a i ϭ a 1 c i , for 1 р i р 2 r . Take any u and in ⌫ at distance r ϩ 1 . We show that there exists a collinearity graph of a generalized 2( r ϩ 1)-gon of order ( a 1 ϩ 1 , c r ϩ 1 Ϫ 1)
In this paper we give a sufficient condition for the existence of a strongly closed subgraph which is (c q + a q )-regular of diameter q containing a given pair of vertices at distance q in a distance-regular graph. Moreover we show that a distance-regular graph with r = max{ j | (c j , a j , b j )