English

Low dimensional flow polytopes and their toric ideals

Commutative Algebra 2021-05-11 v1 Algebraic Geometry

Abstract

The toric ideal of a dd-dimensional flow polytope has an initial ideal generated by square-free monomials of degree at most dd. The toric ideal of a flow polytope of dimension at most four has an initial ideal generated by square-free monomials of degree at most two, with the only exception of the four-dimensional Birkhoff polytope, whose toric ideal has an initial ideal generated by a square-free cubic monomial. The proof is based on a method to classify certain compressed flow polytopes, and a construction of a quadratic pulling triangulation of them. Along the way compressed flow polytopes are classified up to dimension four, and their Ehrhart polynomials are computed.

Cite

@article{arxiv.2105.04004,
  title  = {Low dimensional flow polytopes and their toric ideals},
  author = {Mátyás Domokos and Dániel Joó},
  journal= {arXiv preprint arXiv:2105.04004},
  year   = {2021}
}
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