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• # Artykuł - szczegóły

## Discussiones Mathematicae Graph Theory

2014 | 34 | 1 | 193-198

## Star-Cycle Factors of Graphs

EN

### Abstrakty

EN
A spanning subgraph F of a graph G is called a star-cycle factor of G if each component of F is a star or cycle. Let G be a graph and f : V (G) → {1, 2, 3, . . .} be a function. Let W = {v ∈ V (G) : f(v) = 1}. Under this notation, it was proved by Berge and Las Vergnas that G has a star-cycle factor F with the property that (i) if a component D of F is a star with center v, then degF (v) ≤ f(v), and (ii) if a component D of F is a cycle, then V (D) ⊆ W if and only if iso(G − S) ≤ Σx∈S f(x) for all S ⊂ V (G), where iso(G − S) denotes the number of isolated vertices of G − S. They proved this result by using circulation theory of flows and fractional factors of graphs. In this paper, we give an elementary and short proof of this theorem.

EN

193-198

wydano
2014-02-01
online
2014-02-14

### Twórcy

autor
• Tokyo University of Science, Shinjuku-Ku, Tokyo, Japan
autor
• Ibaraki University, Hitachi, Ibaraki, Japan
autor
• Ibaraki University, Hitachi, Ibaraki, Japan

### Bibliografia

• [1] J. Akiyama and M. Kano, Factors and Factorizations of Graphs (Lecture Notes in Math. 2031, Springer, 2011).
• [2] A. Amahashi and M. Kano, On factors with given components, Discrete Math. 42 (1983) 1-6. doi:10.1016/0012-365X(82)90048-6[Crossref]
• [3] C. Berge and M. Las Vergnas, On the existence of subgraphs with degree constraints, Nederl. Akad. Wetensch. Indag. Math. 40 (1978) 165-176. doi:10.1016/1385-7258(78)90034-3[Crossref]
• [4] M. Las Vergnas, An extension of Tutte‘s 1-factor theorem, Discrete Math. 23 (1978) 241-255. doi:10.1016/0012-365X(78)90006-7[Crossref]
• [5] W.T. Tutte, The 1-factors of oriented graphs, Proc. Amer. Math. Soc. 4 (1953) 922-931. doi:10.2307/2031831[Crossref]