Shingo Sugiyama

collaborators

Showing math.NTShow all

2 papers · 1 filter

math.NT2026

Integrality of Hecke eigenvalues and the growth of Hecke fields

Kenji Sakugawa, Shingo Sugiyama

We prove that Hecke eigenvalues for any Hilbert and Siegel modular forms are algebraic integers. Our method does not rely on cohomologicality nor Galois representations. We apply t…

math.NT2024

A remark on the existence of equivariant functions

Shingo Sugiyama

Let $I^$ be a Fuchsian group in $SL_{2} (R)$ . In this note, we discuss the existence of $I ¨ $ -equivariant functions for a two-dimensional representation $I ¨ $ of $I^$ . Th…