Abstract
We prove that every graph with n vertices and at least 5n−8 edges contains the Petersen graph as a minor, and this bound is best possible. Moreover we characterise all Petersen-minor-free graphs with at least 5n−11 edges. It follows that every graph containing no Petersen minor is 9-colourable and has vertex arboricity at most 5. These results are also best possible.
Original language | English |
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Pages (from-to) | 220-253 |
Number of pages | 34 |
Journal | Journal of Combinatorial Theory, Series B |
Volume | 131 |
DOIs | |
Publication status | Published - 1 Jul 2018 |
Keywords
- Chromatic number
- Extremal function
- Graph minor
- Petersen graph
- Vertex arboricity