Asymptotic expansions for the coefficients of extremal quasimodular forms and a conjecture of Kaneko and Koike

Autor: Peter J. Grabner
Rok vydání: 2021
Předmět:
Zdroj: The Ramanujan Journal. 57:1021-1041
ISSN: 1572-9303
1382-4090
DOI: 10.1007/s11139-020-00368-6
Popis: Extremal quasimodular forms have been introduced by M.~Kaneko and M.Koike as as quasimodular forms which have maximal possible order of vanishing at $i\infty$. We show an asymptotic formula for the Fourier coefficients of such forms. This formula is then used to show that all but finitely many Fourier coefficients of such forms of depth $\leq4$ are positive, which partially solves a conjecture stated by M.~Kaneko and M.Koike. Numerical experiments based on constructive estimates confirm the conjecture for weights $\leq200$ and depths between $1$ and $4$.
Comment: arXiv admin note: text overlap with arXiv:2002.02736
Databáze: OpenAIRE