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A solution is given to the following problem: how to compute the multiplicity, or more generally the Hilbert function, at a point on a Schubert variety in an orthogonal Grassmannian. Standard monomial theory is applied to translate the…

Combinatorics · Mathematics 2009-04-16 K. N. Raghavan , Shyamashree Upadhyay

We prove that Schubert varieties in potentially different Grassmannians are isomorphic as varieties if and only if their corresponding Young diagrams are identical up to a transposition. We also discuss a generalization of this result to…

Algebraic Geometry · Mathematics 2023-09-13 Mihail Tarigradschi , Weihong Xu

We realise the Bott-Samelson resolutions of type A Schubert varieties as quiver Grassmannians. In order to explicitly describe this isomorphism, we introduce the notion of a \textit{geometrically compatible} decomposition for any…

Representation Theory · Mathematics 2025-04-02 Giulia Iezzi

For certain tame abelian covers of arithmetic surfaces X/Y we obtain striking formulas, involving a quadratic form derived from intersection numbers, for the equivariant Euler characteristics of both the canonical sheaf !X/Y and also its…

Number Theory · Mathematics 2010-09-03 Ph. Cassou-Nogu`es , M. J. Taylor

The purpose of this paper is to prove a Pieri-type multiplication formula for quantum Grothendieck polynomials, which was conjectured by Lenart-Maeno. This formula would enable us to compute explicitly the quantum product of two arbitrary…

Quantum Algebra · Mathematics 2024-06-26 Satoshi Naito , Daisuke Sagaki

We develop a combinatorial rule to compute the real geometry of type B Schubert curves $S(\lambda_\bullet)$ in the orthogonal Grassmannian $\mathrm{OG}_n$, which are one-dimensional Schubert problems defined with respect to orthogonal flags…

Combinatorics · Mathematics 2019-03-06 Maria Gillespie , Jake Levinson , Kevin Purbhoo

In this note, we rederive quantum Pieri's formula and the rim hook algorithm in quantum Schubert calculus by studying multiplication in the equivariant cohomology ring of Grassmannians with respect to equivariant Schubert classes which are…

Algebraic Topology · Mathematics 2021-12-07 Chi-Kwong Fok

Tree-level scattering amplitudes of particles have a geometrical description in terms of intersection numbers of pairs of twisted differential forms on the moduli space of Riemann spheres with punctures. We customize a catalog of twisted…

High Energy Physics - Theory · Physics 2022-12-26 Pouria Mazloumi , Stephan Stieberger

The Euler characteristic of a very affine variety encodes the algebraic complexity of solving likelihood (or scattering) equations on this variety. We study this quantity for the Grassmannian with $d$ hyperplane sections removed. We provide…

Algebraic Geometry · Mathematics 2026-04-08 Elia Mazzucchelli , Dmitrii Pavlov , Kexin Wang

This paper works out the versions of the classical Giambelli and Pieri formulas in the context of quantum cohomology of a complex Grassmannian.

alg-geom · Mathematics 2008-02-03 Aaron Bertram

We describe a method of computing equivariant and ordinary intersection cohomology of certain varieties with actions of algebraic tori, in terms of structure of the zero- and one-dimensional orbits. The class of varieties to which our…

Algebraic Geometry · Mathematics 2007-05-23 Tom Braden , Robert MacPherson

In the recent paper [arXiv:1612.06893] P. B\"urgisser and A. Lerario introduced a geometric framework for a probabilistic study of real Schubert Problems. They denoted by $\delta_{k,n}$ the average number of projective $k$-planes in…

Algebraic Geometry · Mathematics 2019-12-19 Antonio Lerario , Léo Mathis

We describe the torus-equivariant cohomology ring of isotropic Grassmannians by using a localization map to the torus fixed points. We present two types of formulas for equivariant Schubert classes of these homogeneous spaces. The first…

Algebraic Geometry · Mathematics 2007-05-23 Takeshi Ikeda , Hiroshi Naruse

We study the T-equivariant quantum cohomology of the Grassmannian. We prove the vanishing of a certain class of equivariant quantum Littlewood-Richardson coefficients, which implies an equivariant quantum Pieri rule. As in the equivariant…

Algebraic Geometry · Mathematics 2007-05-23 Leonardo C. Mihalcea

The quantum cohomology ring of the Grassmannian is determined by the quantum Pieri rule for multiplying by Schubert classes indexed by row or column-shaped partitions. We provide a direct equivariant generalization of Postnikov's quantum…

Combinatorics · Mathematics 2022-01-20 Anna Bertiger , Dorian Ehrlich , Elizabeth Milićević , Kaisa Taipale

We give a combinatorial rule for computing intersection numbers on a flag manifold which come from products of Schubert classes pulled back from Grassmannian projections. This rule generalizes the known rule for Grassmannians.

Combinatorics · Mathematics 2008-05-03 Kevin Purbhoo , Frank Sottile

Let $V$ be a possibly singular scheme-theoretic complete intersection subscheme of $\mathbb{P}^n$ over an algebraically closed field of characteristic zero. Using a recent result of Fullwood ("On Milnor classes via invariants of singular…

Algebraic Geometry · Mathematics 2017-11-15 Martin Helmer

The isotropic Grassmannian parametrizes isotropic subspaces of a vector space equipped with a quadratic form. In this paper, we show that any maximal isotropic Grassmannian in its Pl\"ucker embedding can be defined by pulling back the…

Algebraic Geometry · Mathematics 2023-08-21 Tim Seynnaeve , Nafie Tairi

In a classical-type flag variety, we consider a Schubert variety associated to a vexillary (signed) permutation, and establish a combinatorial formula for the Hilbert-Samuel multiplicity of a point on such a Schubert variety. The formula is…

Algebraic Geometry · Mathematics 2021-12-15 David Anderson , Takeshi Ikeda , Minyoung Jeon , Ryotaro Kawago

For varieties given by an equation N_{K/k}(\Xi)=P(t), where N_{K/k} is the norm form attached to a field extension K/k and P(t) in k[t] is a polynomial, three topics have been investigated: (1) computation of the unramified Brauer group of…

Number Theory · Mathematics 2014-06-09 Dasheng Wei