## Abstract

We apply the Hecke operators T(p)2 and (1 ≤ j ≤ n ≤ 2k) to a degree n theta series attached to a rank 2k ℤ-lattice L equipped with a positive definite quadratic form in the case that L/pL is regular. We explicitly realize the image of the theta series under these Hecke operators as a sum of theta series attached to certain sublattices of , thereby generalizing the Eichler Commutation Relation. We then show that the average theta series (averaging over isometry classes in a given genus) is an eigenform for these operators. We explicitly compute the eigenvalues on the average theta series, extending previous work where we had the restrictions that χ(p) = 1 and n ≤ k. We also show that for j > k when χ(p) = 1, and for j ≥ k when χ(p) = -1, and that θ(gen L) is an eigenform for T(p)2.

Translated title of the contribution | Actioin of Hecke operators on Siegel theta series, II |
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Original language | English |

Pages (from-to) | 981 - 1008 |

Number of pages | 28 |

Journal | International Journal of Number Theory |

Volume | 4 |

Issue number | 6 |

DOIs | |

Publication status | Published - Dec 2008 |