There exists an open –manifold and a simple closed curve such that is infinitely generated, is finitely generated and the preimage of in the universal covering of is equivalent to the standard locally finite set of vertical lines in , that is, the trivial link of infinitely many components in .
"Covering a nontaming knot by the unlink." Algebr. Geom. Topol. 7 (3) 1561 - 1578, 2007. https://doi.org/10.2140/agt.2007.7.1561