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We describe a construction of Gromov-Witten invariants for flag varieties and use it to give a presentation for the quantum cohomology ring, by extending the ideas used by Bertram in the case of Grassmannians. This provides a proof for the…

alg-geom · Mathematics 2008-02-03 Ionuţ Ciocan-Fontanine

Springer fibers are subvarieties of the flag variety parametrized by partitions; they are central objects of study in geometric representation theory. Schubert varieties are subvarieties of the flag variety that induce a well-known basis…

Combinatorics · Mathematics 2018-10-12 Martha Precup , Julianna Tymoczko

Let $P$ be a parabolic subgroup in $G=SL_n(\mathbf k)$, for $\mathbf k$ an algebraically closed field. We show that there is a $G$-stable closed subvariety of an affine Schubert variety in an affine partial flag variety which is a natural…

Algebraic Geometry · Mathematics 2022-03-29 Venkatramani Lakshmibai , Rahul Singh

In the framework of the problem of characterizing complete flag manifolds by their contractions, the complete flags of type $F_4$ and $G_2$ satisfy the property that any possible tower of Bott-Samelson varieties dominating them birationally…

Algebraic Geometry · Mathematics 2022-02-24 Gianluca Occhetta , Luis E. Solá Conde

We describe the effect of Feigin's flat degeneration of the type $\textrm{A}$ flag variety on its Schubert varieties. In particular, we study when they stay irreducible and in several cases we are able to encode reducibility of the…

Representation Theory · Mathematics 2023-02-21 Lara Bossinger , Martina Lanini

We show how the families Seiberg-Witten invariants of a family of smooth $4$-manifolds can be recovered from the families Bauer-Furuta invariant via a cohomological formula. We use this formula to deduce several properties of the families…

Differential Geometry · Mathematics 2022-05-03 David Baraglia , Hokuto Konno

We give positive formulas for the restriction of a Schubert Class to a T-fixed point in the equivariant K-theory and equivariant cohomology of the Lagrangian Grassmannian. Our formulas rely on a result of Ghorpade-Raghavan, which gives an…

Algebraic Geometry · Mathematics 2007-05-23 V. Kreiman

We classify smooth Schubert varieties S_0 in a rational homogeneous manifold S associated to a short root, and show that they are rigid in the sense that any subvariety of S having the same homology class as S_0 is induced by the action of…

Algebraic Geometry · Mathematics 2019-07-24 Jaehyun Hong , Minhyuk Kwon

We prove a Chevalley formula for the equivariant quantum multiplication of two Schubert classes in the homogeneous variety X=G/P. As in the case when X is a Grassmannian, studied by the author in a previous paper, this formula implies an…

Algebraic Geometry · Mathematics 2007-05-23 Leonardo Constantin Mihalcea

Let $N\subset GL(n,R)$ be the group of upper triangular matrices with $1$s on the diagonal, equipped with the standard Carnot group structure. We show that quasiconformal homeomorphisms between open subsets of $N$, and more generally…

Differential Geometry · Mathematics 2022-08-02 Bruce Kleiner , Stefan Muller , Xiangdong Xie

We study the back stable $K$-theory Schubert calculus of the infinite flag variety. We define back stable (double) Grothendieck polynomials and double $K$-Stanley functions and establish coproduct expansion formulae. Applying work of…

Combinatorics · Mathematics 2021-08-24 Thomas Lam , Seung Jin Lee , Mark Shimozono

Let X be the flag variety of the symplectic group. We propose a theory of combinatorially explicit Schubert polynomials which represent the Schubert classes in the Borel presentation of the cohomology ring of X. We use these polynomials to…

Algebraic Geometry · Mathematics 2014-02-26 Harry Tamvakis

We construct equivariant and Bott-type Seiberg-Witten Floer homology and cohomology for 3-manifolds, in particular rational homology spheres, and prove their diffeomorphism invariance. We present several versions of the equivariant theory:…

Geometric Topology · Mathematics 2007-05-23 Rugang Ye

The quantum cohomology algebra of the (full) flag manifold is a fundamental example in quantum cohomology theory, with connections to combinatorics, algebraic geometry, and integrable systems. Using a differential geometric approach, we…

Differential Geometry · Mathematics 2007-05-23 A. Amarzaya , M. A. Guest

This survey paper describes two geometric representations of the permutation group using the tools of toric topology. These actions are extremely useful for computational problems in Schubert calculus. The (torus) equivariant cohomology of…

Algebraic Topology · Mathematics 2007-06-05 Julianna S. Tymoczko

We prove a conjecture of A. S. Buch concerning the structure constants of the Grothendieck ring of a flag variety with respect to its basis of Schubert structure sheaves. For this, we show that the coefficients in this basis of the…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion

We introduce new notions in elliptic Schubert calculus: the (twisted) Borisov-Libgober classes of Schubert varieties in general homogeneous spaces G/P. While these classes do not depend on any choice, they depend on a set of new variables.…

Algebraic Geometry · Mathematics 2019-10-08 Shrawan Kumar , Richárd Rimányi , Andrzej Weber

Using a transversality argument, we demonstrate the positivity of certain coefficients in the equivariant cohomology and K-theory of a generalized flag manifold. This strengthens earlier equivariant positivity theorems (of Graham and…

Algebraic Geometry · Mathematics 2023-02-27 David Anderson

In this paper, we study the homogeneous components of the Chern--Schwartz--MacPherson (CSM) classes of Schubert cells. We prove that, under suitable conditions, each such component is represented by an irreducible subvariety. In particular,…

Algebraic Geometry · Mathematics 2026-03-27 Yuxiang Liu , Artan Sheshmani , Shing-Tung Yau

Let G be a complex semisimple linear algebraic group and let Pet be the associated Peterson variety in the flag variety G/B. The main theorem of this note gives an efficient presentation of the equivariant cohomology ring H^*_S(Pet) of the…

Algebraic Geometry · Mathematics 2019-08-15 Megumi Harada , Tatsuya Horiguchi , Mikiya Masuda