The existence of a function a(k) (where k is a natural number) is established such that the vertex set of any graph G of minimum degree at least a ( k ) has a decomposition A U B U C such that G(A) has minimum degree a t least k , each vertex of A is joined to at least k vertices of B, and no two ve
On graph decompositions modulo k
β Scribed by A.D. Scott
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 153 KB
- Volume
- 175
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
We prove that, for every integer k >~ 2, every graph has an edge-partition into 5k 2 log k sets, each of which is the edge-set of a graph with all degrees congruent to 1 mod k. This answers a question of Pyber.
Pyber proved that every graph G has an edge-partition into four sets, each of which is the edge-set of a graph with all degrees odd; if every component of G has even order then three sets will do. This is best possible, as can be seen by considering Ks with two independent edges removed, which cannot be partitioned into fewer than four subgraphs with all degrees odd; and/Β£4 with one edge removed, which requires three. Motivated by this result, Pyber asked what happens when we consider residues modk, rather than mod2. In particular, he asked whether for every integer k there is an integer c(k) such that every graph has an edge-partition into at most c(k) sets, each of which is the edge-set of a graph with all degrees congruent to 1 modk. The following theorem answers this question.
π SIMILAR VOLUMES
## Abstract Generalizing the wellβknown concept of an __i__βperfect cycle system, Pasotti [Pasotti, in press, Australas J Combin] defined a Ξβdecomposition (Ξβfactorization) of a complete graph __K__~__v__~ to be __iβperfect__ if for every edge [__x__, __y__] of __K__~__v__~ there is exactly one bl
dedicated to professor w. t. tutte on the occasion of his eightieth birthday Let G=(V, E) be an Eulerian graph embedded on a triangulizable surface S. We show that E can be decomposed into closed curves C 1 , ..., C k such that mincr(G, D)= k i=1 mincr(C i , D) for each closed curve D on S. Here min