Published online by Cambridge University Press: 18 January 2021
Let M be a closed, connected, orientable topological $4$ -manifold, and G be a finite group acting topologically and locally linearly on M. In this paper, we investigate the spectral sequence for the Borel cohomology $H^*_G(M)$ and establish new bounds on the rank of G for homologically trivial actions with discrete singular set.
This project was partially supported by NSERC Discovery Grant A4000. The first author wishes to thank the Max Planck Institut für Mathematik for its hospitality and support in November 2019. The second author was supported on sabbatical by METU and thanks McMaster University for its hospitality during the academic year 2018–19.