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Related papers: A geometric interpretation of the Delta Conjecture

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We define a torus $U \subset T = (\mathbb{C}^\times)^K$ which acts on the $\Delta$-Springer varieties $Y_{n,\lambda,s}$ defined by Griffin-Levinson-Woo and give a Borel-style presentation for the equivariant cohomology ring…

Algebraic Geometry · Mathematics 2026-05-01 Raymond Chou

The affine Grassmannian of $SL_n$ admits an embedding into the Sato Grassmannian, which further admits a Pl\"ucker embedding into the projectivization of Fermion Fock space. Kreiman, Lakshmibai, Magyar, and Weyman describe the linear part…

Algebraic Geometry · Mathematics 2018-06-18 Dinakar Muthiah , Alex Weekes , Oded Yacobi

In this paper, we formulate a rational analog of the fall Delta theorem and the Delta square conjecture. We find a new dinv statistic on fall-decorated paths on a $(m+k) \times (n+k)$ rectangle that simultaneously extends the previously…

Combinatorics · Mathematics 2025-08-29 Alessandro Iraci , Roberto Pagaria , Giovanni Paolini

According to Laumon, an affine Springer fiber is homeomorphic to the universal abelian covering of the compactified Jacobian of a spectral curve. We construct equivariant deformations $f_{n}:\overline{\mathcal{P}}_{n}\to \mathcal{B}_{n}$ of…

Algebraic Geometry · Mathematics 2024-04-15 Zongbin Chen

A classical and beautiful story in geometric representation theory is the construction by Springer of an action of the Weyl group on the cohomology of the fibres of the Springer resolution of the nilpotent cone. We establish a natural…

Algebraic Geometry · Mathematics 2026-05-06 Kevin McGerty , Thomas Nevins

We study spherical Schubert varieties in the affine Grassmannian. These Schubert varieties have a natural conjectural modular description due to Finkelberg-Mirkovi\'c. This modular description is easily seen to be set-theoretically correct,…

Representation Theory · Mathematics 2016-04-04 Joel Kamnitzer , Dinakar Muthiah , Alex Weekes

We compute the Borel-Moore homology of unramified affine Springer fibers for $\mathrm{GL}_n$ under the assumption that they are equivariantly formal and relate them to certain ideals discussed by Haiman. For $n=3$, we give an explicit…

Algebraic Geometry · Mathematics 2024-08-14 Joshua P. Turner

The symmetric group $\mathfrak{S}_n$ acts on the polynomial ring $\mathbb{Q}[\mathbf{x}_n] = \mathbb{Q}[x_1, \dots, x_n]$ by variable permutation. The invariant ideal $I_n$ is the ideal generated by all $\mathfrak{S}_n$-invariant…

Combinatorics · Mathematics 2019-04-04 James Haglund , Brendon Rhoades , Mark Shimozono

For any formal group law, there is a formal affine Hecke algebra defined by Hoffnung, Malag\'on-L\'opez, Savage, and Zainoulline. Coming from this formal group law, there is also an oriented cohomology theory. We identify the formal affine…

Representation Theory · Mathematics 2015-01-28 Gufang Zhao , Changlong Zhong

In the context of the shuffle theorem, many classical integer sequences appear with a natural refinement by two statistics $q$ and $t$: for example the Catalan and Schr\"oder numbers. In particular, the bigraded Hilbert series of diagonal…

Combinatorics · Mathematics 2024-03-29 Sylvie Corteel , Matthieu Josuat-Vergès , Anna Vanden Wyngaerd

We show that Hilbert schemes of planar curve singularities and their parabolic variants can be interpreted as certain generalized affine Springer fibers for $GL_n$, as defined by Goresky-Kottwitz-MacPherson. Using a generalization of affine…

Algebraic Geometry · Mathematics 2022-01-28 Niklas Garner , Oscar Kivinen

We find a new geometric incarnation for the principal block in the category of modules over a quantum group at a root of unity, realizing it as a full subcategory of microsheaves on a certain affine Springer fiber. We also prove a related…

Algebraic Geometry · Mathematics 2026-04-15 Roman Bezrukavnikov , Pablo Boixeda Alvarez , Michael McBreen , Zhiwei Yun

Given a representation N of a reductive group G, Braverman-Finkelberg-Nakajima have defined a remarkable Poisson variety called the Coulomb branch. Their construction of this space was motivated by considerations from 3d gauge theories and…

Representation Theory · Mathematics 2023-08-02 Justin Hilburn , Joel Kamnitzer , Alex Weekes

A key tool for the study of an affine Hecke algebra $\mathcal{H}$ is provided by Springer theory of the Langlands dual group via the realization of $\mathcal{H}$ as equivariant $K$-theory of the Steinberg variety. We prove a similar…

Representation Theory · Mathematics 2024-10-08 Roman Bezrukavnikov , Ivan Karpov , Vasily Krylov

We introduce the higher rank $(q,t)$-Catalan polynomials and prove they equal truncations of the Hikita polynomial to a finite number of variables. Using affine compositions and a certain standardization map, we define a dinv statistic on…

Combinatorics · Mathematics 2023-03-29 Nicolle González , José Simental , Monica Vazirani

We prove the Extended Delta Conjecture of Haglund, Remmel, and Wilson, a combinatorial formula for $\Delta _{h_l}\Delta' _{e_k} e_{n}$, where $\Delta' _{e_k}$ and $\Delta_{h_l}$ are Macdonald eigenoperators and $e_n$ is an elementary…

Combinatorics · Mathematics 2021-08-31 Jonah Blasiak , Mark Haiman , Jennifer Morse , Anna Pun , George H. Seelinger

Theory of motivic superpolynomials is developed, including its extension to algebraic links colored by rows, relations to $L$-functions of plane curve singularities, the justification of the motivic versions of Weak Riemann Hypothesis, and…

Quantum Algebra · Mathematics 2025-08-26 Ivan Cherednik

We study equivariant Seiberg-Witten Floer theory of rational homology $3$-spheres in the special case where the group action is given by an involution. The case of involutions deserves special attention because we can couple the involution…

Geometric Topology · Mathematics 2024-03-04 David Baraglia , Pedram Hekmati

In this article, first we give two formulae for the delta invariant of a complex curve singularity that can be embedded as a ${\mathbb Q}$-Cartier divisor in a normal surface singularity with rational homology sphere link. Next, we consider…

Algebraic Geometry · Mathematics 2025-11-06 Zsolt Baja , Tamás László , András Némethi

Given a semisimple element in the loop Lie algebra of a reductive group, we construct a quasi-coherent sheaf on a partial resolution of the trigonometric commuting variety of the Langlands dual group. The construction uses affine Springer…

Algebraic Geometry · Mathematics 2025-02-04 Eugene Gorsky , Oscar Kivinen , Alexei Oblomkov