Algebraic aspects of hypergeometric differential equations

T Reichelt, M Schulze, C Sevenheck… - Beiträge zur Algebra und …, 2021 - Springer
We review some classical and modern aspects of hypergeometric differential equations,
including A-hypergeometric systems of Gel'′ fand, Graev, Kapranov and Zelevinsky. Some …

Irregular hypergeometric D-modules

MC Fernández-Fernández - Advances in Mathematics, 2010 - Elsevier
We study the irregularity of hypergeometric D-modules MA (β) via the explicit construction of
Gevrey series solutions along coordinate subspaces in X= Cn. As a consequence, we prove …

Nilsson solutions for irregular -hypergeometric systems

A Dickenstein, FN Martínez, LF Matusevich - Revista Matematica …, 2012 - ems.press
We study the solutions of irregular A-hypergeometric systems that are constructed from
Gröbner degenerations with respect to generic positive weight vectors. These are formal …

Dualizing, projecting, and restricting GKZ systems

A Steiner - Journal of Pure and Applied Algebra, 2019 - Elsevier
Let A be an integer matrix, and assume that its semigroup ring C [NA] is normal. Fix a face F
of the cone of A. We show that the projection and restriction of an A-hypergeometric system …

Gevrey solutions of irregular hypergeometric systems in two variables

MC Fernández-Fernández, FJ Castro-Jiménez - Journal of Algebra, 2011 - Elsevier
We describe the Gevrey series solutions at singular points of the irregular hypergeometric
system (GKZ system) associated with an affine plane monomial curve. We also describe the …

Restriction of hypergeometric 𝒟-modules with respect to coordinate subspaces

MC Fernández-Fernández, U Walther - Proceedings of the American …, 2011 - JSTOR
RESTRICTION OF HYPERGEOMETRIC 𝒟-MODULES WITH RESPECT TO COORDINATE
SUBSPACES Page 1 PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY Volume …

Gevrey expansions of hypergeometric integrals I

FJ Castro-Jiménez, M Granger - … Mathematics Research Notices, 2015 - ieeexplore.ieee.org
We study integral representations of the Gevrey series solutions of irregular hypergeometric
systems. In this paper, we consider the case of the systems associated with a one-row …

Irregular modified 𝐴-hypergeometric systems

FJ Castro-Jiménez, MC Fernández-Fernández… - Transactions of the …, 2015 - ams.org
A modified $ A $-hypergeometric system is a system of differential equations for the function
$ f (t^ w\cdot x) $, where $ f (y) $ is a solution of an $ A $-hypergeometric system in $ n …

On irregular binomial D-modules

MC Fernández-Fernández, FJ Castro-Jiménez - Mathematische Zeitschrift, 2012 - Springer
We prove that a holonomic binomial D-module MA (I, β) is regular if and only if certain
associated primes of I determined by the parameter vector β ∈ C^ d are homogeneous. We …

[HTML][HTML] Gevrey and formal Nilsson solutions of A-hypergeometric systems

MC Fernandez-Fernandez - Journal of Pure and Applied Algebra, 2020 - Elsevier
We prove that the space of Gevrey solutions of an A–hypergeometric system along a
coordinate subspace is contained in a space of formal Nilsson solutions. Moreover, under …