{ "id": "2202.03159", "version": "v1", "published": "2022-02-07T13:36:08.000Z", "updated": "2022-02-07T13:36:08.000Z", "title": "$L^2$-Betti numbers and computability of reals", "authors": [ "Clara Loeh", "Matthias Uschold" ], "comment": "35 pages; Lean implementation available at https://gitlab.com/L2-comp/l2-comp-lean", "categories": [ "math.GR", "cs.LO", "math.GT", "math.LO" ], "abstract": "We study the computability degree of real numbers arising as $L^2$-Betti numbers or $L^2$-torsion of groups, parametrised over the Turing degree of the word problem. Moreover, we explain how such considerations can be modelled in a proof assistant.", "revisions": [ { "version": "v1", "updated": "2022-02-07T13:36:08.000Z" } ], "analyses": { "keywords": [ "betti numbers", "computability degree", "word problem", "proof assistant", "turing degree" ], "note": { "typesetting": "TeX", "pages": 35, "language": "en", "license": "arXiv", "status": "editable" } } }