Polyedrische 2-Mannigfaltigkeiten mit wenigen nicht-konvexen Ecken.
Projections of knots
Properly homotopic nontrivial planes are isotopic
It is proved that two planes that are properly homotopic in a noncompact, orientable, irreducible 3-manifold that is not homeomorphic to are isotopic. The end-reduction techniques of E. M. Brown and C. D. Feustal and M. G. Brin and T. L. Thickstun are used.