References
[B] Brown, K.S.: Cohomology of groups. (Grad. Texts Math., vol. 87) Berlin Heidelburg New York: Springer 1982
[BBE] Ballmann, W., Brin, N., Eberlein, P.: Structure of manifolds of nonpositive curvature I. Ann. Math.122, 171–203 (1985)
[BGS] Ballmann, W., Gromov, M., Schroeder, V.: Manifolds of nonpositive curvature. Basel Boston: Birkhäuser 1985
[CS] Croke, C., Schroeder, V.: The fundamental group of compact manifolds without conjugate points. Comment. Math. Helv.61, 161–175 (1986)
[F] Fox, R.: Covering spaces with singularities. Algebraic geometry and topology. A symposium in honor of S. Lefschetz, Princeton: Princeton University Press (1957)
[G] Gromov, M.: Manifolds of negative curvature. J. Differ Geom.13, 223–230 (1978)
[GT] Gromov, M., Thurston, W.: Pinching constants for hyperbolic manifolds. Invent. Math.89, 1–12 (1987)
[GW] Gromoll, D., Wolf, J.: Some relations between the metric structure and the algebraic structure of the fundamental group in manifolds of nonpositive curvature. Bull. Am. Math. Soc.77, 545–552, (1971)
[LY] Lawson, B., Yau, S.T.: Compact manifolds of non positive curvature. J. Differ Geom.7, 211–228 (1972)
[R] Rolfsen, D.: Knots and links. Boston: Publish or Perish (1976)
Author information
Authors and Affiliations
Additional information
Partially supported by CNPq, Brazil
Supported by CNPq, Brazil and GMD, Germany
Rights and permissions
About this article
Cite this article
Fornari, S., Schroeder, V. Ramified coverings with nonpositive curvature. Math Z 203, 123–128 (1990). https://doi.org/10.1007/BF02570726
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02570726