English

The Chirotropical Grassmannian

Combinatorics 2025-11-25 v2 High Energy Physics - Theory Algebraic Geometry

Abstract

Recent developments in particle physics have revealed deep connections between scattering amplitudes and tropical geometry. From the heart of this relationship emerged the chirotropical Grassmannian TropχG(k,n)\text{Trop}^\chi \text{G}(k,n) and the chirotropical Dressian Drχ(k,n)\text{Dr}^\chi(k,n), polyhedral fans built from uniform realizable chirotopes that encode the combinatorial structure of Generalized Feynman Diagrams. We prove that TropχG(3,n)=Drχ(3,n)\text{Trop}^\chi \text{G}(3,n) = \text{Dr}^\chi(3,n) for n=6,7,8n = 6,7,8, and develop algorithms to compute these objects from their rays modulo lineality. Using these algorithms, we compute all chirotropical Grassmannians TropχG(3,n)\text{Trop}^\chi \text{G}(3,n) for n=6,7,8n = 6,7,8 across all isomorphism classes of chirotopes. We prove that each chirotopal configuration space Xχ(3,6)X^\chi(3,6) is diffeomorphic to a polytope and propose an associated canonical logarithmic differential form. Finally, we show that the equality between chirotropical Grassmannian and Dressian fails for (k,n)=(4,8)(k,n) = (4,8).

Keywords

Cite

@article{arxiv.2411.07293,
  title  = {The Chirotropical Grassmannian},
  author = {Dario Antolini and Nick Early},
  journal= {arXiv preprint arXiv:2411.07293},
  year   = {2025}
}

Comments

General improvements to the exposition. Added details in Section 6 on CEGM integrands and canonical forms. 13 pages, 1 figure

R2 v1 2026-06-28T19:56:00.660Z