Gröbner methods for representations of combinatorial categories

S Sam, A Snowden - Journal of the American Mathematical Society, 2017 - ams.org
Given a category $\mathcal {C} $ of a combinatorial nature, we study the following
fundamental question: how do combinatorial properties of $\mathcal {C} $ affect algebraic …

Big polynomial rings and Stillman's conjecture

D Erman, SV Sam, A Snowden - Inventiones mathematicae, 2019 - Springer
The purpose of this paper is to prove that certain limits of polynomial rings are themselves
polynomial rings, and show how this observation can be used to deduce some interesting …

[HTML][HTML] Equivariant Hilbert series in non-noetherian polynomial rings

U Nagel, T Römer - Journal of Algebra, 2017 - Elsevier
We introduce and study equivariant Hilbert series of ideals in polynomial rings in countably
many variables that are invariant under a suitable action of a symmetric group or the monoid …

[HTML][HTML] FI-and OI-modules with varying coefficients

U Nagel, T Römer - Journal of Algebra, 2019 - Elsevier
We introduce FI-algebras over a commutative ring K and the category of FI-modules over an
FI-algebra. Such a module may be considered as a family of invariant modules over …

Free descriptions of convex sets

E Levin, V Chandrasekaran - arXiv preprint arXiv:2307.04230, 2023 - arxiv.org
Convex sets arising in a variety of applications are well-defined for every relevant
dimension. Examples include the simplex and the spectraplex that correspond, respectively …

Noetherianity of some degree two twisted commutative algebras

R Nagpal, SV Sam, A Snowden - Selecta Mathematica, 2016 - Springer
The resolutions of determinantal ideals exhibit a remarkable stability property: for fixed rank
but growing dimension, the terms of the resolution stabilize (in an appropriate sense). One …

Castelnuovo–Mumford regularity up to symmetry

DV Le, U Nagel, HD Nguyen… - International Mathematics …, 2021 - academic.oup.com
We study the asymptotic behavior of the Castelnuovo–Mumford regularity along chains of
graded ideals in increasingly larger polynomial rings that are invariant under the action of …

Codimension and projective dimension up to symmetry

DV Le, U Nagel, HD Nguyen… - Mathematische …, 2020 - Wiley Online Library
Symmetric ideals in increasingly larger polynomial rings that form an ascending chain are
investigated. We focus on the asymptotic behavior of codimensions and projective …

Betti numbers of symmetric shifted ideals

J Biermann, H De Alba, F Galetto, S Murai, U Nagel… - Journal of Algebra, 2020 - Elsevier
We introduce a new class of monomial ideals which we call symmetric shifted ideals.
Symmetric shifted ideals are fixed by the natural action of the symmetric group and, within …

Asymptotic behavior of symmetric ideals: A brief survey

M Juhnke-Kubitzke, DV Le, T Römer - … in Algebra and Geometry: NSA 26 …, 2020 - Springer
Recently, chains of increasing symmetric ideals have attracted considerable attention. In this
note, we summarize some results and open problems concerning the asymptotic behavior of …