Christian Haase ; Gregg Musiker ; Josephine Yu
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Linear Systems on Tropical Curves
dmtcs:2847 -
Discrete Mathematics & Theoretical Computer Science,
January 1, 2010,
DMTCS Proceedings vol. AN, 22nd International Conference on Formal Power Series and Algebraic Combinatorics (FPSAC 2010)
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https://doi.org/10.46298/dmtcs.2847
Linear Systems on Tropical CurvesArticle
Authors: Christian Haase 1; Gregg Musiker 2; Josephine Yu 3
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Christian Haase;Gregg Musiker;Josephine Yu
1 Institute of Mathematics [Berlin]
2 Department of Mathematics [MIT]
3 School of Mathematics - Georgia Institute of Technology
A tropical curve $\Gamma$ is a metric graph with possibly unbounded edges, and tropical rational functions are continuous piecewise linear functions with integer slopes. We define the complete linear system $|D|$ of a divisor $D$ on a tropical curve $\Gamma$ analogously to the classical counterpart. We investigate the structure of $|D|$ as a cell complex and show that linear systems are quotients of tropical modules, finitely generated by vertices of the cell complex. Using a finite set of generators, $|D|$ defines a map from $\Gamma$ to a tropical projective space, and the image can be modified to a tropical curve of degree equal to $\mathrm{deg}(D)$. The tropical convex hull of the image realizes the linear system $|D|$ as a polyhedral complex.