scholarly journals Multiplicity-Free Schubert Calculus

2010 ◽  
Vol 53 (1) ◽  
pp. 171-186 ◽  
Author(s):  
Hugh Thomas ◽  
Alexander Yong
Keyword(s):  
Algebraic Geometry ◽  
Schubert Calculus ◽  
Chow Ring ◽  
Free Products ◽  
Linear Basis ◽  
Combinatorial Classification ◽  
Schubert Classes ◽  
Multiplicity Free

AbstractMultiplicity-free algebraic geometry is the study of subvarieties Y ⊆ X with the “smallest invariants” as witnessed by a multiplicity-free Chow ring decomposition of [Y] ∈ A*(X) into a predetermined linear basis.This paper concerns the case of Richardson subvarieties of the Grassmannian in terms of the Schubert basis. We give a nonrecursive combinatorial classification of multiplicity-free Richardson varieties, i.e., we classify multiplicity-free products of Schubert classes. This answers a question of W. Fulton.

scholarly journals Fine-structure classification of multiqubit entanglement by algebraic geometry

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Masoud Gharahi ◽  
Stefano Mancini ◽  
Giorgio Ottaviani
Keyword(s):  
Algebraic Geometry ◽  
Fine Structure

scholarly journals Classification of $Q$-Multiplicity-Free Skew Schur $Q$-Functions

10.37236/6494 ◽  
2017 ◽  
Vol 24 (2) ◽  
Author(s):  
Christopher Schure
Keyword(s):  
Multiplicity Free

We classify the $Q$-multiplicity-free skew Schur $Q$-functions. Towards this result, we also provide new relations between the shifted Littlewood-Richardson coefficients.

scholarly journals Combinatorial classification of quantum lens spaces

2018 ◽  
Vol 297 (2) ◽  
pp. 339-365
Author(s):  
Peter Jensen ◽  
Frederik Klausen ◽  
Peter Rasmussen
Keyword(s):  
Lens Spaces ◽  
Combinatorial Classification

Quadratic-monomial generated domains from mixed signed, directed graphs

2019 ◽  
Vol 29 (02) ◽  
pp. 279-308
Author(s):  
Michael A. Burr ◽  
Drew J. Lipman
Keyword(s):  
Directed Graphs ◽  
Complete Characterization ◽  
Combinatorial Structure ◽  
Signed Directed Graph ◽  
Odd Cycle ◽  
Combinatorial Classification ◽  
Special Case ◽  
Text Condition

Determining whether an arbitrary subring [Formula: see text] of [Formula: see text] is a normal or Cohen-Macaulay domain is, in general, a nontrivial problem, even in the special case of a monomial generated domain. We provide a complete characterization of the normality, normalizations, and Serre’s [Formula: see text] condition for quadratic-monomial generated domains. For a quadratic-monomial generated domain [Formula: see text], we develop a combinatorial structure that assigns, to each quadratic monomial of the ring, an edge in a mixed signed, directed graph [Formula: see text], i.e. a graph with signed edges and directed edges. We classify the normality and the normalizations of such rings in terms of a generalization of the combinatorial odd cycle condition on [Formula: see text]. We also generalize and simplify a combinatorial classification of Serre’s [Formula: see text] condition for such rings and construct non-Cohen–Macaulay rings.

scholarly journals A Classification of Multiplicity Free Actions

1996 ◽  
Vol 181 (1) ◽  
pp. 152-186 ◽  
Author(s):  
Chal Benson ◽  
Gail Ratcliff
Keyword(s):  
Multiplicity Free ◽  
Free Actions

scholarly journals On Multiplicity-Free Skew Characters and the Schubert Calculus

2010 ◽  
Vol 14 (3) ◽  
pp. 339-353 ◽  
Author(s):  
Christian Gutschwager
Keyword(s):  
Schubert Calculus ◽  
Multiplicity Free ◽  
Skew Characters

scholarly journals A Complete Classification of 3-dimensional Quadratic AS-regular Algebras of Type EC

2020 ◽  
pp. 1-19
Author(s):  
Masaki Matsuno
Keyword(s):  
Algebraic Geometry ◽  
Complete Classification ◽  
Complete List ◽  
Graded Algebra ◽  
Regular Algebra ◽  
3 Dimensional ◽  
Noncommutative Algebraic Geometry ◽  
Regular Algebras ◽  
Point Scheme

Abstract Classification of AS-regular algebras is one of the main interests in noncommutative algebraic geometry. We say that a $3$ -dimensional quadratic AS-regular algebra is of Type EC if its point scheme is an elliptic curve in $\mathbb {P}^{2}$ . In this paper, we give a complete list of geometric pairs and a complete list of twisted superpotentials corresponding to such algebras. As an application, we show that there are only two exceptions up to isomorphism among all $3$ -dimensional quadratic AS-regular algebras that cannot be written as a twist of a Calabi–Yau AS-regular algebra by a graded algebra automorphism.

scholarly journals On Schubert calculus in elliptic cohomology

2015 ◽  
Vol DMTCS Proceedings, 27th... (Proceedings) ◽  
Author(s):  
Cristian Lenart ◽  
Kirill Zainoulline
Keyword(s):  
Formal Group ◽  
Schubert Calculus ◽  
Elliptic Cohomology ◽  
Reduced Word ◽  
Combinatorial Result ◽  
International Audience ◽  
Schubert Classes ◽  
K Theory ◽  
Nous Utilisons ◽  
Group Law

International audience An important combinatorial result in equivariant cohomology and $K$-theory Schubert calculus is represented by the formulas of Billey and Graham-Willems for the localization of Schubert classes at torus fixed points. These formulas work uniformly in all Lie types, and are based on the concept of a root polynomial. We define formal root polynomials associated with an arbitrary formal group law (and thus a generalized cohomology theory). We usethese polynomials to simplify the approach of Billey and Graham-Willems, as well as to generalize it to connective $K$-theory and elliptic cohomology. Another result is concerned with defining a Schubert basis in elliptic cohomology (i.e., classes independent of a reduced word), using the Kazhdan-Lusztig basis of the corresponding Hecke algebra. Un résultat combinatoire important dans le calcul de Schubert pour la cohomologie et la $K$-théorie équivariante est représenté par les formules de Billey et Graham-Willems pour la localisation des classes de Schubert aux points fixes du tore. Ces formules sont uniformes pour tous les types de Lie, et sont basés sur le concept d’un polynôme de racines. Nous définissons les polynômes formels de racines associées à une loi arbitraire de groupe formel (et donc à une théorie de cohomologie généralisée). Nous utilisons ces polynômes pour simplifier les preuves de Billey et Graham-Willems, et aussi pour généraliser leurs résultats à la $K$-théorie connective et la cohomologie elliptique. Un autre résultat concerne la définition d’une base de Schubert dans cohomologie elliptique (c’est à dire, des classes indépendantes d’un mot réduit), en utilisant la base de Kazhdan-Lusztig de l’algèbre de Hecke correspondant.

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