Abstract
The vertex arboricity va(G) of a graph G is the minimum number of colors the vertices can be labeled so that each color class induces a forest. It was well-known that va(G)≤3 for every planar graph G. In this paper, we prove that va(G)≤2 if G is a planar graph without 7-cycles. This extends a result in [A. Raspaud, W. Wang, On the vertex-arboricity of planar graphs, European J. Combin. 29 (2008) 1064-1075] that for each k∈3,4,5,6, planar graphs G without k-cycles have va(G)≤2.
| Original language | English |
|---|---|
| Pages (from-to) | 2304-2315 |
| Number of pages | 12 |
| Journal | Discrete Mathematics |
| Volume | 312 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - 6 Aug 2012 |
User-Defined Keywords
- Cycle
- Planar graph
- Vertex arboricity