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The affine Springer fiber corresponding to $GL_{4}$ and regular semi-simple integral split element admits an affine paving, so its cohomology is "pure".

Representation Theory · Mathematics 2012-11-13 Zongbin Chen

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

For the group $\mathrm{GL}_{n}$ and the anisotropic elements, we confirm the purity hypothesis of Goresky, Kottwitz and MacPherson, which states that the affine Springer fibers are cohomologically pure in the sense of Grothendieck-Deligne.

Algebraic Geometry · Mathematics 2026-05-27 Zongbin Chen

For any connected reductive group $G$ over $\mathbb{C}$, we revisit Goresky-Kottwitz-MacPherson's description of the torus equivariant Borel-Moore homology of affine Springer fibers $\mathrm{Sp}_\gamma\subset \mathrm{Gr}_G$, where…

Algebraic Geometry · Mathematics 2019-09-10 Oscar Kivinen

The affine Springer fiber corresponding to a regular integral equivalued semisimple element admits a paving by vector bundles over Hessenberg varieties and hence its (Borel-Moore) homology is "pure".

Representation Theory · Mathematics 2007-05-23 Mark Goresky , Robert Kottwitz , Robert MacPherson

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

We identify, up to homeomorphisms, the affine Springer fibers for GL(n) on a local field of equal characteristics with some coverings of compactified jacobians of singular projective curves. This allows us to prove an irreducibility…

Algebraic Geometry · Mathematics 2007-05-23 Gerard Laumon

We address questions posed by G\'erard Laumon and Jean-Loup Waldspurger concerning the cohomological purity of affine Springer fibers. More precisely, we show that an affine Springer fiber is cohomologically pure if and only if its…

Algebraic Geometry · Mathematics 2026-05-08 Zongbin Chen

We state a conjecture on how to construct affine pavings for cohomologically pure projective algebraic varieties, which admit an action of torus such that the fixed points and $1$-dimensional orbits are finite. Experiments on the affine…

Algebraic Geometry · Mathematics 2014-01-10 Zongbin Chen

Assuming the purity conjecture for the affine Springer fibers which has been formulated by Goresky, Kottwitz and MacPherson, we prove a geometric analog of the fundamental lemma for unitary groups. Our approach is similar to the one of…

Algebraic Geometry · Mathematics 2007-05-23 Gerard Laumon

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

We study basic geometric properties of some group analogue of affine Springer fibers and compare with the classical Lie algebra affine Springer fibers. The main purpose is to formulate a conjecture that relates the number of irreducible…

Algebraic Geometry · Mathematics 2018-05-24 Jingren Chi

We show that the cohomology ring of Hilbert scheme of $n$-points in the affine plane is isomorphic to the coordinate ring of $\mathbb{G}_{m}$-fixed point scheme of the $n$-th symmetric product of $\mathbb{C}^{2}$ for a natural…

Algebraic Geometry · Mathematics 2015-01-13 Tatsuyuki Hikita

Let $\mathcal{I}_{d,g,R}$ be the union of irreducible components of the Hilbert scheme whose general points parametrize smooth, irreducible, curves of degree $d$, genus $g$, which are non--degenerate in the projective space $\mathbb{P}^R$.…

Algebraic Geometry · Mathematics 2021-12-22 Flaminio Flamini , Paola Supino

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

We denote by $\mathcal{H}_{d,g,r}$ the Hilbert scheme of smooth curves, which is the union of components whose general point corresponds to a smooth irreducible and non-degenerate curve of degree $d$ and genus $g$ in $\mathbb{P}^r$. In this…

Algebraic Geometry · Mathematics 2025-03-25 Changho Keem

We define certain closed subvarieties of the flag variety, Hessenberg ideal fibers, and prove that they are paved by affines. Hessenberg ideal fibers are a natural generalization of Springer fibers. In type $G_2$, we give explicit…

Algebraic Geometry · Mathematics 2024-06-28 Ke Xue

We calculate the Borel-Moore homology of affine Springer fibers of type $A$ associated to some regular semisimple nil elliptic elements. As a result, we obtain bigraded $\mf{S}_{n}$-modules whose bigraded Frobenius series are generalization…

Algebraic Geometry · Mathematics 2012-03-28 Tatsuyuki Hikita

We classify fibrations by integral plane projective rational quartic curves whose generic fibre is regular but admits a non-smooth point that is a canonical divisor. These fibrations can only exist in characteristic two. The geometric…

Algebraic Geometry · Mathematics 2025-10-27 Cesar Hilario , Karl-Otto Stöhr

Let $\mathcal{I}_{d,g,r}$ be the union of irreducible components of the Hilbert scheme whose general points correspond to smooth irreducible non-degenerate curves of degree $d$ and genus $g$ in $\mathbb{P}^r$. We use families of curves on…

Algebraic Geometry · Mathematics 2020-03-17 Youngook Choi , Hristo Iliev , Seonja Kim
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