Families of Gröbner Degenerations, Grassmannians and Universal Cluster Algebras

• Published in: Symmetry, Integrability and Geometry: Methods and Applications
• Date: 2021
• Main Authors: Bossinger, Lara, Mohammadi, Fatemeh, Nájera Chávez, Alfredo
• Format: Article
• Language: English
• Published: Інститут математики НАН України 2021
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/211364
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Families of Gröbner Degenerations, Grassmannians and Universal Cluster Algebras. Lara Bossinger, Fatemeh Mohammadi and Alfredo Nájera Chávez. SIGMA 17 (2021), 059, 46 pages

Let be the weighted projective variety defined by a weighted homogeneous ideal and a maximal cone in the Gröbner fan of with rays. We construct a flat family over ᵐ that assembles the Gröbner degenerations of associated with all faces of . This is a multi-parameter generalization of the classical one-parameter Gröbner degeneration associated with a weight. We explain how our family can be constructed from Kaveh-Manon's recent work on the classification of toric flat families over toric varieties: it is the pull-back of a toric family defined by a Rees algebra with base C (the toric variety associated to ) along the universal torsor ᵐ → C. We apply this construction to the Grassmannians Gr(2, ℂⁿ) with their Plücker embeddings and the Grassmannian Gr(3, ℂ⁶) with its cluster embedding. In each case, there exists a unique maximal Gröbner cone whose associated initial ideal is the Stanley-Reisner ideal of the cluster complex. We show that the corresponding cluster algebra with universal coefficients arises as the algebra defining the flat family associated with this cone. Further, for Gr(2, ℂⁿ), we show how Escobar-Harada's mutation of Newton-Okounkov bodies can be recovered as a tropicalized cluster mutation.