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Characterization of knot complements in the n-sphere

Vo-Thanh Liem, Gerard Venema (1995)

Fundamenta Mathematicae

Knot complements in the n-sphere are characterized. A connected open subset W of S n is homeomorphic with the complement of a locally flat (n-2)-sphere in S n , n ≥ 4, if and only if the first homology group of W is infinite cyclic, W has one end, and the homotopy groups of the end of W are isomorphic to those of S 1 in dimensions less than n/2. This result generalizes earlier theorems of Daverman, Liem, and Liem and Venema.

Contact topology and the structure of 5-manifolds with π 1 = 2

Hansjörg Geiges, Charles B. Thomas (1998)

Annales de l'institut Fourier

We prove a structure theorem for closed, orientable 5-manifolds M with fundamental group π 1 ( M ) = 2 and second Stiefel-Whitney class equal to zero on H 2 ( M ) . This structure theorem is then used to construct contact structures on such manifolds by applying contact surgery to fake projective spaces and certain 2 -quotients of  S 2 × S 3 .

Continuity of Barycentric Coordinates in Euclidean Topological Spaces

Karol Pąk (2011)

Formalized Mathematics

In this paper we present selected properties of barycentric coordinates in the Euclidean topological space. We prove the topological correspondence between a subset of an affine closed space of εn and the set of vectors created from barycentric coordinates of points of this subset.

Detecting codimension one manifold factors with the piecewise disjoint arc-disk property and related properties

Denise Halverson, Dušan Repovš (2013)

Open Mathematics

We show that all finite-dimensional resolvable generalized manifolds with the piecewise disjoint arc-disk property are codimension one manifold factors. We then show how the piecewise disjoint arc-disk property and other general position properties that detect codimension one manifold factors are related. We also note that in every example presently known to the authors of a codimension one manifold factor of dimension n ≥ 4 determined by general position properties, the piecewise disjoint arc-disk...

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