JournalscmhVol. 74, No. 1pp. 150–155

Approximating 2\ell_2-Betti numbers of an amenable covering by ordinary Betti numbers

  • B. Eckmann

    Eidgenössische Technische Hochschule, Zürich, Switzerland
Approximating $\ell_2$-Betti numbers of an amenable covering by ordinary Betti numbers cover
Download PDF

Abstract

It is shown that the 2\ell_2-Betti numbers of an amenable covering of a finite cell-complex can be approximated by ordinary Betti numbers of the finite Fmlner subcomplexes. This is a new proof, using simple homological arguments, of a recent result of Dodziuk and Mathai.

Cite this article

B. Eckmann, Approximating 2\ell_2-Betti numbers of an amenable covering by ordinary Betti numbers. Comment. Math. Helv. 74 (1999), no. 1, pp. 150–155

DOI 10.1007/S000140050081