Symplectic modular symbols
arXiv:math/9809059
Abstract
Let K be a number field with euclidean ring of integers O. Let G be a finite-index torsion-free subgroup of Sp(2n, O). We exhibit a finite, geometrically defined spanning set of the top dimensional integral cohomology of G by generalizing the modular symbol algorithm of Ash and Rudolph.
21 pages, 8 figures, AMS-LaTeX, uses psfrag.sty, incorporates referee's comments