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Yoichi Mieda

Publications and source records attributed to Yoichi Mieda.

At least 19 recordsLinked to original sources
arXiv2019

On the formal degree conjecture for simple supercuspidal representations

We prove the formal degree conjecture for simple supercuspidal representations of symplectic groups and quasi-split even special orthogonal groups over a p-adic field, under the assumption that p is odd. The essential part is to compute the Swan conductor of the exterior square of an irreducible local Galois representation with Swan conductor 1. It is carried out by passing to the equal characteristic local field and using the theory of Kloosterman sheaves.

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arXiv2018

Galois representations associated with a non-selfdual automorphic representation of GL(3)

In 1994, van Geemen and Top constructed a non-selfdual motive of rank three over $\mathbb{Q}$ conjecturally associated with a cuspidal non-selfdual automorphic representation of $\mathrm{GL}_3(\mathbb{A}_{\mathbb{Q}})$ of level $Γ_0(128)$. They experimentally confirmed the coincidence of the local $L$-factors at finitely many primes using computer. In this paper, we shall prove the coincidence of the local $L$-factors at every prime. To show this, we use the recent results of Harris-Lan-Taylor-Thorne and Scholze on the construction of Galois representations, and Grenié's results to compare three-dimensional $2$-adic Galois representations. We also prove the local-global compatibility at $p = 2$, including the case $p = \ell$.

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arXiv2018

On irreducible components of Rapoport-Zink spaces

Under a mild condition, we prove that the action of the group of self-quasi-isogenies on the set of irreducible components of a Rapoport-Zink space has finite orbits. Our method allows both ramified and non-basic cases. As a consequence, we obtain some finiteness results on the representation obtained from the l-adic cohomology of a Rapoport-Zink tower.

math.AG↗
arXiv2017

Potentially good reduction loci of Shimura varieties

In this paper, we give a notion of the potentially good reduction locus of a Shimura variety. It consists of the points which should be related with motives having potentially good reductions in some sense. We show the existence of such locus for a Shimura variety of preabelian type. Further, we construct a partition of the adic space associated to a Shimura variety of preabelian type, which is expected to describe degenerations of motives. Using this partition, we prove that the cohomology of the potentially good reduction locus is isomorphic to the cohomology of a Shimura variety up to non-supercuspidal parts.

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arXiv2016

Geometric approach to the explicit local Langlands correspondence

We propose a geometric strategy of giving explicit description of the Langlands parameter of an irreducible supercuspidal representation of GL(n) over a non-archimedean local field. The key is to compare the cohomology of an affinoid in the Lubin-Tate space at infinite level and that of the reduction of its formal model. As examples, we treat the cases of depth 0 supercuspidal representations and simple supercuspidal representations.

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arXiv2012

Lefschetz trace formula for open adic spaces

In this article, we discuss the Lefschetz trace formula for an adic space which is separated smooth of finite type but not necessarily proper over an algebraically closed non-archimedean field. Under a certain condition on the absence of set-theoretical fixed points on the boundary, we obtain a fixed point formula. As an application, we can establish a trace formula for some formal schemes, which is applicable to the Rapoport-Zink tower for GSp(4). A partial generalization of Fujiwara's trace formula for contracting morphisms is also given.

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arXiv2011

Geometric approach to the local Jacquet-Langlands correspondence

In this paper, we give a purely geometric approach to the local Jacquet-Langlands correspondence for GL(n) over a p-adic field, under the assumption that the invariant of the division algebra is 1/n. We use the l-adic etale cohomology of the Drinfeld tower to construct the correspondence at the level of the Grothendieck groups with rational coefficients. Moreover, assuming that n is prime, we prove that this correspondence preserves irreducible representations. This gives a purely local proof of the local Jacquet-Langlands correspondence in this case. We need neither a global automorphic technique nor detailed classification of supercuspidal representations of GL(n).

math.RT↗
arXiv2011

On the cohomology of the Lubin-Tate curve of level 2 and the Lusztig theory over finite rings

An etale cohomology group $W$ of some irreducible components, which is the smooth compactification of an affine curve $(X^{q^2}-X)^{q-1}=(Y^{q(q+1)}-Y^{q+1})^{q-1},$ in the stable reduction the Lubin-Tate curve of level two is related to the Lusztig theory over finite rings. In this paper, we investigate a relationship between the cohomology group $W$ and the Lusztig theory.

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arXiv2011

On the cuspidal representations of ${\rm GL}_2(F)$ of level 1 or 1/2 in the cohomology of the Lubin-Tate space $\mathcal{X}(π^2)$

In this paper, we compute irreducible components which appear in the stable reduction of the Lubin-Tate curve of level two, in the mixed characteristic case. We also compute the action of the central division algebra of invariant 1/2, the action of ${\rm GL}_2$, and the inertia action explicitly. As a result, in a sense, we observe that, in the cohomology group of the stable reduction of the Lubin-Tate curve for ${\rm GL}_2$, the local Langlands correspondence and the local Jacquet-Langlands correspondence for ${\rm GL}_2$ are realized for the cuspidal representations of level 1 or 1/2.

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arXiv2011

Compactly supported cohomology and nearby cycle cohomology of open Shimura varieties of PEL type

In this paper, we compare two cohomology groups associated to Shimura varieties of PEL type, which are not proper over the base. One is the compactly supported l-adic cohomology, and the other is the nearby cycle cohomology, namely, the compactly supported cohomology of the nearby cycle complex for the canonical integral model of the Shimura variety over Z_p. We prove that the G(Q_p)-cuspidal part of these cohomology groups are the same, where G denotes the reductive algebraic group naturally attached to the PEL datum. Some applications to unitary Shimura varieties are also given.

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arXiv2010

Cuspidal representations in the l-adic cohomology of the Rapoport-Zink space for GSp(4)

In this paper, we study the l-adic cohomology of the Rapoport-Zink tower for GSp(4). We prove that the smooth representation of GSp_4(Q_p) obtained as the i-th compactly supported l-adic cohomology of the Rapoport-Zink tower has no quasi-cuspidal subquotient unless i=2,3,4. Our proof is purely local and does not require global automorphic methods.

math.RT↗
arXiv2010

Variants of formal nearby cycles

In this paper, we introduce variants of formal nearby cycles for a locally noetherian formal scheme over a complete discrete valuation ring. If the formal scheme is locally algebraizable, then our nearby cycle gives a generalization of Berkovich's formal nearby cycle. Our construction is entirely scheme-theoretic and does not require rigid geometry. Our theory is intended for applications to the local study of the cohomology of Rapoport-Zink spaces.

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