Enumerating Polytropes

Series
Algebra Seminar
Time
Monday, October 6, 2014 - 3:05pm for 1 hour (actually 50 minutes)
Location
Skiles 005
Speaker
Ngoc Mai Tran – UT Austin – https://www.ma.utexas.edu/users/ntran/
Organizer
Josephine Yu
Polytropes are both ordinary and tropical polytopes. Tropical types of polytropes in \R^n are in bijection with certain cones of a specific Gr\"obner fan in \R^{n^2-n}. Unfortunately, even for n = 5 the entire fan is too large to be computed by existing software. We show that the polytrope cones can be decomposed as the cones from the refinement of two fans, intersecting with a specific cone. This allows us to enumerate types of full-dimensional polytropes for $n = 4$, and maximal polytropes for $n = 5$ and $n = 6$. In this talk, I will prove the above result and describe the key difficulty in higher dimensions.