An orthogonal double cover (ODC) of Kn is a collection of graphs such that each edge of Kn occurs in exactly two of the graphs and two graphs have precisely one edge in common. ODCs of Kn and their generalizations have been extensively studied by several authors (e.g. in:
On DRC-covering of Kn by cycles
β Scribed by Jean-Claude Bermond; David Coudert; Min-Li Yu
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 173 KB
- Volume
- 11
- Category
- Article
- ISSN
- 1063-8539
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
This paper considers the cycle covering of complete graphs motivated by the design of survivable WDM networks, where the requests are routed on INFβnetworks which are protected independently from each other. The problem can be stated as follows: for a given graph G, find a cycle covering of the edge set of K~n~, where V(K~n~) = V(G), such that each cycle in the covering satisfies the disjoint routing constraint (DRC7rpar;, relatively to G, which can be stated as follows: to each edge of K~n~ we associate in G a path and all the paths associated to the edges of a cycle of the covering must be vertex disjoint. Here we consider the case where G = C~n~, a ring of size n and we want to minimize the number of cycles in the covering. We give optimal solutions for the problem as well as for variations of the problem, namely, its directed version and the case when the cycle length is fixed to 4. Β© 2003 Wiley Periodicals, Inc. J Combin Designs 11: 100β112, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jcd.10040
π SIMILAR VOLUMES
The main theorem of that paper is the following: let G be a graph of order n, of size at least (nZ -3n + 6 ) / 2 . For any integers k, n,, n2,. . . , nk such that n = n, + n2 + ... + nk and n, 2 3, there exists a covering of the vertices of G by disjoint cycles (C,),=,..,k with ICjl = n,, except whe
the vertices of a digraph by cycles of prescribed length, Discrete Mathematics 87 (
It is shown that if a graph has a cycle double cover, then its line graph also has a cycle double cover. The converse of this result for 2-edge-connected graphs would imply the truth of the cycle double cover conjecture. Cycle Double Cover Conjecture (CDCC). Every 2-edge-connected graph has a CDC.
A collection = {GI, CZ, . . . , C,} of spanning subgraphs of K, is called an orthogonal double cover if (i) every edge of K , belongs to exactly two of the Ci's and (ii) any two distinct Ci's intersect in exactly one edge. Chung and West conjectured that there exists an orthogonal double cover of K,