Mathematisches Seminar, Universit{ät} Kiel, 24098 Kiel, Germany ; Fakultät für Mathematik, Ruhr-Universität Bochum, 44780 Bochum, Germany ; Department of Mathematics, Indian Institute of Technology, Powai, Mumbai 400076, India
Abstract:
Let be a Hadamard manifold of dimension whose sectional curvature satisfies and whose curvature tensor satisfies for suitable constants and . We show that is of constant sectional curvature provided is asymptotically harmonic. This was previously only known if admits a compact quotient.