Spezielle Konjugationsklassen der Modulgruppe vierten Grades und Stufe \(q>2\). (Special conjugacy classes of the modular group of degree 4 and level \(>2)\) (Q909702)

Let \(\Gamma\) (n,q) denote the principal congruence subgroup of level q of the Siegel modular group of degree n. If one wants to apply the Selberg trace formula in order to calculate the dimension of the space of cusp forms of weight k for \(\Gamma\) (n,q), one needs to know the conjugacy classes of \(\Gamma\) (n,q). In the paper under review the author considers the case \(n=4\), \(q>2\) and those classes of matrices, which are expected to give a contribution to the dimension integral, i.e., the characteristic polynomial of the matrices is equal to \((X-1)^ 8.\) In this situation she explicitly states a representative of each conjugacy class.