Abstract
This paper compares the divisorial gonality of a finite graph G to the divisorial gonality of the associated metric graph Γ(G,1) with unit lengths. We show that dgon(Γ(G,1)) is equal to the minimal divisorial gonality of all regular subdivisions of G, and we provide a class of graphs for which this number is strictly smaller than the divisorial gonality of G. This settles a conjecture of M. Baker [3, Conjecture 3.14] in the negative.
Original language | English |
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Article number | 105619 |
Pages (from-to) | 1-19 |
Journal | Journal of Combinatorial Theory. Series A |
Volume | 189 |
DOIs | |
Publication status | Published - Jul 2022 |
Bibliographical note
Funding Information:We are grateful to Dion Gijswijt, Sophie Huiberts and Alejandro Vargas for helpful discussions. The first author is partially supported by the Dutch Research Council (NWO), project number 613.009.127 . The second author would like to thank the Max Planck Institute for Mathematics Bonn for its financial support.
Publisher Copyright:
© 2022 The Author(s)
Funding
We are grateful to Dion Gijswijt, Sophie Huiberts and Alejandro Vargas for helpful discussions. The first author is partially supported by the Dutch Research Council (NWO), project number 613.009.127 . The second author would like to thank the Max Planck Institute for Mathematics Bonn for its financial support.
Keywords
- Chip-firing game
- Finite graph
- Gonality
- Metric graph