English

Tropical and Ordinary Convexity Combined

Combinatorics 2010-03-24 v3 Commutative Algebra

Abstract

A polytrope is a tropical polytope which at the same time is convex in the ordinary sense. A dd-dimensional polytrope turns out to be a tropical simplex, that is, it is the tropical convex hull of d+1d+1 points. This statement is equivalent to the known fact that the Segre product of two full polynomial rings (over some field KK) has the Gorenstein property if and only if the factors are generated by the same number of indeterminates. The combinatorial types of polytropes up to dimension three are classified.

Keywords

Cite

@article{arxiv.0801.4835,
  title  = {Tropical and Ordinary Convexity Combined},
  author = {Michael Joswig and Katja Kulas},
  journal= {arXiv preprint arXiv:0801.4835},
  year   = {2010}
}

Comments

revised proof of Theorem 7; a few more results and references added

R2 v1 2026-06-21T10:08:11.480Z