Involutive modular transformations on the Siegel upper half plane and an application to representations of quadratic forms
Involutive modular transformations on the Siegel upper half plane and an application to representations of quadratic forms
复制标题
西格尔上半平面上的对合模变换及其在二次形式表示中的应用
DOI:
10.1016/0022-314x(86)90007-7
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发表时间:
1986
影响因子:
0.7
通讯作者:
Robert Sibner
中科院分区:
文献类型:
--
作者:
K. Hashimoto;Robert Sibner
We establish a one-to-one correspondence between the set of conjugacy classes of elliptic transformations in Sp (n, Z) which satisfy X 2+ I= 0 (resp. X 2+ X+ I= 0) and the set of hermitian forms of rank n over Z [√− 1](resp. Z [(− 1+√− 3)/2]) of determinant±1. As an application, we generalize, to positive symmetric integral matrices S of rank n, the classical fact that any divisor of m 2+ 1 (resp. m+ m+ 1) can be represented by the quadratic form F (X, Y)= X 2+ Y 2 (resp. X 2+ XY+ Y 2) with relatively prime integers X, Y: Suppose n≤ 3 (resp. n≤ 5). Then S can be represented over Z by F⊗ n (n copies of F) if det S is represented by F as above. The proof is based on Siegel-Braun's Mass formula for hermitian forms.