On the representation of numbers by the direct sums of some quaternary quadratic forms
The author constructs explicit bases for the spaces of cusp forms \(S_{2m} (\Gamma_0(5), \chi^m)\) and\break \(S_{2m} (\Gamma_0(13), \chi^m)\) for all integers \(m\geq 2\). Then he gets certain explicit formulas for the representation numbers by direct sums of \(m\) summands of quaternary quadratic forms of discriminant 5 (resp. 13) for \(m= 2,\dots, 6\) (resp. \(2,\dots, 5)\).
scientific article; zbMATH DE number 1621371