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Related papers: Monodromy and Irreducibility of Igusa Varieties

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Let $S$ be a closed Shimura variety uniformized by the complex $n$-ball. The Hodge conjecture predicts that every Hodge class in $H^{2k} (S, \Q)$, $k=0, \ldots, n$, is algebraic. We show that this holds for all degree $k$ away from the…

Algebraic Geometry · Mathematics 2014-06-04 Nicolas Bergeron , John Millson , Colette Moeglin

We study the integral models of meta-unitary Shimura varieties through the lens of Scholze's fiber product conjecture. Reformulating Bultel's original construction in terms of moduli stacks of Shtukas and Igusa stacks, we prove the validity…

Algebraic Geometry · Mathematics 2026-04-14 Ali Partofard

We present a general and comprehensive overview of recent developments in the theory of integral models of Shimura varieties of Hodge type. The paper covers the following topics: construction of integral models, their possible moduli…

Number Theory · Mathematics 2008-08-12 Adrian Vasiu

We prove the isogeny property for special fibres of integral canonical models of compact Shimura varieties of $A_n$, $B_n$, $C_n$, and $D_n^{\dbR}$ type. The approach used also shows that many crystalline cycles on abelian varieties over…

Number Theory · Mathematics 2012-10-25 Adrian Vasiu

We review the Newton stratification and Ekedahl-Oort stratification on the special fiber of a smooth integral model for a Shimura variety of Hodge type at a prime of good reduction. We show that the \mu-ordinary locus coincides with the…

Algebraic Geometry · Mathematics 2013-10-25 Daniel Wortmann

We construct canonical non-vanishing global sections of powers of the Hodge bundle on each Ekedahl-Oort stratum of a Hodge type Shimura variety. In particular we recover the quasi-affineness of the Ekedahl-Oort strata. In the projective…

Algebraic Geometry · Mathematics 2014-10-30 Jean-Stefan Koskivirta

I employ methods from derived algebraic geometry to give a uniform moduli-theoretic construction of special cycle classes on integral models many Shimura varieties of Hodge type, including unitary, quaternionic, and orthogonal Shimura…

Number Theory · Mathematics 2023-06-05 Keerthi Madapusi

We provide a simple and efficient numerical criterion to verify the Iwasawa main conjecture and the indivisibility of derived Kato's Euler systems for modular forms of weight two at any good prime under mild assumptions. In the ordinary…

Number Theory · Mathematics 2020-03-16 Chan-Ho Kim , Myoungil Kim , Hae-Sang Sun

I construct a generalisation of Mantovan's almost product structure to Shimura varieties of Hodge type with hyperspecial level structure at $p$ and deduce that the perfection of the Newton strata are pro-\'etale locally isomorphic to the…

Algebraic Geometry · Mathematics 2018-10-29 Paul Hamacher

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

We propose a conjecture on the $p$-adic nowhere density of the Hecke orbit of subvarieties of Hodge type Shimura varieties. By investigating the monodromy of $p$-adic Galois representations associated with points on such Shimura varieties,…

Number Theory · Mathematics 2025-06-10 Yu Fu

In this article, we generalize the work of H.Hida and V.Pilloni to construct $p$-adic families of $\mu$-ordinary modular forms on Shimura varieties of Hodge type $Sh(G,X)$ associated to a Shimura datum $(G,X)$ where $G$ is a connected…

Number Theory · Mathematics 2021-04-27 Xiaoyu Zhang

We study the Iwasawa main conjecture for quadratic Hilbert modular forms over the p-cyclotomic tower. Using an Euler system in the cohomology of Siegel modular varieties, we prove the "Kato divisibility" of the Iwasawa main conjecture under…

Number Theory · Mathematics 2025-02-19 David Loeffler , Sarah Livia Zerbes

We compute the connected components of arbitrary parahoric level affine Deligne-Lusztig varieties and local Shimura varieties, thus resolving a folklore conjecture in full generality (even for non-quasisplit groups). We achieve this by…

Number Theory · Mathematics 2025-11-11 Ian Gleason , Dong Gyu Lim , Yujie Xu

T. Mochizuki constructs a theory of variations of wild Hodge structure for which the underlying flat connection can have irregular singularities at infinity. He extends in this way the correspondence of Corlette and Simpson between…

Algebraic Geometry · Mathematics 2013-12-10 Claude Sabbah

Igusa varieties over the special fibre of Shimura varieties have demonstrated many applications to the Langlands program via Mantovan's formula and Shin's point counting method. In this paper we study Igusa varieties over the moduli stack…

Algebraic Geometry · Mathematics 2025-11-05 Paul Hamacher , Wansu Kim

We prove a conjecture of Hiraga-Ichino-Ikeda relating formal degrees of square-integrable representations to adjoint gamma factors for symplectic and even orthogonal groups over characteristic zero non-Archimedean local fields. The proof is…

Representation Theory · Mathematics 2025-08-13 Raphaël Beuzart-Plessis

We study the mod $p$-points of the Kisin--Pappas integral models of Shimura varieties of Hodge type with parahoric level. We show that if the group is quasi-split, then every isogeny class contains the reduction of a CM point, proving a…

Number Theory · Mathematics 2024-12-10 Pol van Hoften

We study the special fiber of the integral models for Shimura varieties of Hodge type with parahoric level structure constructed by Kisin and Pappas in [KP]. We show that when the group is residually split, the points in the mod $p$ isogeny…

Number Theory · Mathematics 2020-12-23 Rong Zhou

We prove the Morrison--Kawamata cone conjecture for projective primitive symplectic varieties with $\Q$-factorial and terminal singularities with $b_2\geq 5$, from which we derive for instance the finiteness of minimal models of such…

Algebraic Geometry · Mathematics 2022-08-01 Christian Lehn , Giovanni Mongardi , Gianluca Pacienza