Full paper in PDF:
$%J. M. Montesinos-Amilibia, Representing open 3-manifolds as 3-fold branched coverings,
Rev. Mat. Complut. 15 (2002), no. 2, 533-542.%$
RESUMEN
La compactificación de Freudenthal de una 3-variedad abierta conexa y orientable es una cubierta de 3 hojas ramificada sobre S3 y, en ciertos casos, de dos hojas. La ramificación es una unión localmente finita y disjunta de cuerdas.
ABSTRACT
It is proved that the Freudenthal compactification of an open, connected, oriented 3-manifold is a 3-fold branched covering of S3, and in some cases, a 2-fold branched covering of S3.The branching set is a locally finite disjoint union of strings.
2000 Mathematics Subject Classification: 57M12, 57M30, 57N10.