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19972026
most citedEisenstein congruences for SO(4,3), SO(4,4), spinor and triple product L-values

2 citations · 3 across the 10 of their papers we have counts for

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math.NT2026

Modules of Jacobi forms of degree two of small levels

Hiroki Aoki, Tomoyoshi Ibukiyama

The purpose of this paper is to describe explicitly the modules of (Siegel-)Jacobi forms of degree two of index one of any scalar valued weight with respect to some congruence subg…

math.NT2025

Hermitian modular forms and algebraic modular forms on

Tomoyoshi Ibukiyama, Brandon Williams

We state conjectures that relate Hermitian modular forms of degree two and algebraic modular forms for the compact group . We provide evidence for these conjectures in the f…

math.NT2024

Formal series of Jacobi forms

Hiroki Aoki, Tomoyoshi Ibukiyama, Cris Poor

We prove for general paramodular level that formal series of scalar Jacobi forms with an involution condition necessarily converge and are therefore the Fourier-Jacobi expansions a…

math.NT2023

Period of the Ikeda-Miyawaki lift

Tomoyoshi Ibukiyama, Hidenori Katsurada, Hisashi Kojima

In this paper, first we give a weak version of Ikeda's conjecture on the period of the Ikeda-Miyawaki lift. Next, we confirm this conjecture rigorously in some cases.

math.NT2023

Harder's conjecture II

Hiraku Atobe, Masataka Chida, Tomoyoshi Ibukiyama +2

Let be a primitive form of weight for , and let be a prime ideal of the Hecke field of . We denote by the Siegel modular group of degree .…

math.NT2023

Genus character -functions of quadratic orders in an adelic way and maximal orders of matrix algebras

Tomoyoshi Ibukiyama

For a quadratic extension of , we consider orders in that are not necessarily maximal and the ideal class group in the narrow sense of proper ide…

math.NT2022

Dimensions of paramodular forms and compact twist modular forms with involutions

Tomoyoshi Ibukiyama

We give an explicit dimension formula for paramodular forms of degree two of prime level with plus or minus sign of the Atkin--Lehner involution of weight $\det^k\operatorname{Sym}…

math.NT2022

When is a polarised abelian variety determined by its -divisible group?

Tomoyoshi Ibukiyama, Valentijn Karemaker, Chia-Fu Yu

We study the Siegel modular variety of genus and its supersingular locus . As our main result we determine precis…

math.NT2021

Harder's conjecture I

Hiraku Atobe, Masataka Chida, Tomoyoshi Ibukiyama +2

Let be a primitive form with respect to . Then we propose a conjecture on the congruence between the Klingen-Eisenstein lift of the Duke-Imamoglu-Ikeda lift of and…

math.NT2016★ 2 cited

Eisenstein congruences for SO(4,3), SO(4,4), spinor and triple product L-values

Jonas Bergström, Neil Dummigan, Thomas Mégarbané

We work out instances of a general conjecture on congruences between Hecke eigenvalues of induced and cuspidal automorphic representations of a reductive group, modulo divisors of…

math.NT2012★ 1 cited

Jacobi forms that characterize paramodular forms

Tomoyoshi Ibukiyama, Cris Poor, David S. Yuen

The Fourier Jacobi expansions of paramodular forms are characterized from among all formal series of Jacobi forms by two conditions on the Fourier coeffcients of the Jacobi forms:…