The **coefficient ring ** of a Siegel modular form is the subring $\Z[{a_n}]$ of $\C$ generated by the coefficients $a_n$ of its $q$-expansion $\sum a_nq^n$. In the case of a newform the coefficients $a_n$ are algebraic integers and the coefficient ring is a finite index subring of the ring of integers of the coefficient field of the newform.
It is also known as the **Hecke ring**, since the $a_n$ generate the same ring as the eigenvalues of the Hecke operators.

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- Review status: beta
- Last edited by Eran Assaf on 2022-08-31 11:05:24

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