Non-metrizable manifolds and contractibility
Year: 2025
Type: article
Abstract: We investigate whether non-metrizable manifolds in various classes can be homotopy equivalent to a CW-complex (in short: heCWc),and in particular contractible. We show that a non-metrizable manifold cannot be heCWc if it has one of the following properties: it contains a countably compact non-compact subspace; it contains a copy of an ω1-compact subspace of an ω1-tree; it contains a non-Lindelöf closed subspace functionally narrow in it. (These results hold for more general spaces than just manifolds.) We also show that the positive part of the tangent bundle of the longray is never heCWc for any smoothing. These theorems follow from stabilization properties of real valued maps. On a more geometric side, we also show that the Prüfer surface, which has been shown to be contractible long ago, has an open submanifold with trivial homotopy groups which is not heCWc. On the other end of the spectrum, we show that there is a non-metrizable contractible Type I surface.
Source: Applied General Topology
Author: Mathieu Baillif
Institution: HES-SO Genève
Language: English
Subfield: Geometry and Topology
Field: Mathematics
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4409049062