{ "id": "2305.03927", "version": "v1", "published": "2023-05-06T04:50:23.000Z", "updated": "2023-05-06T04:50:23.000Z", "title": "The Borel complexity of the space of left-orderings, low-dimensional topology, and dynamics", "authors": [ "Filippo Calderoni", "Adam Clay" ], "comment": "23 pages", "categories": [ "math.LO", "math.GR", "math.GT" ], "abstract": "We find new criteria to analyze the complexity of the conjugacy equivalence relation $E_\\mathsf{lo}(G)$ for a given left-orderable group $G$. We show that $E_\\mathsf{lo}(G)$ is universal whenever $G$ is the free product of left-orderable groups, and that $E_\\mathsf{lo}(G)$ is not smooth whenever $G$ is simple and not bi-orderable, or when $G$ admits a closed $G$-invariant family of non-Conradian orderings. We apply these new criteria to study the smoothness of $E_\\mathsf{lo}(G)$ when $G$ is the fundamental group of $3$-manifold, and by using tools related to the L-space conjecture we show that if $G$ is a non-cyclic knot group, then $E_\\mathsf{lo}(G)$ is not smooth.", "revisions": [ { "version": "v1", "updated": "2023-05-06T04:50:23.000Z" } ], "analyses": { "keywords": [ "borel complexity", "low-dimensional topology", "left-orderings", "conjugacy equivalence relation", "left-orderable group" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }