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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.

Cocycle invariants of codimension 2 embeddings of manifolds

Józef H. Przytycki, Witold Rosicki (2014)

Banach Center Publications

We consider the classical problem of a position of n-dimensional manifold Mⁿ in n + 2 . We show that we can define the fundamental (n+1)-cycle and the shadow fundamental (n+2)-cycle for a fundamental quandle of a knotting M n + 2 . In particular, we show that for any fixed quandle, quandle coloring, and shadow quandle coloring, of a diagram of Mⁿ embedded in n + 2 we have (n+1)- and (n+2)-(co)cycle invariants (i.e. invariant under Roseman moves).

Crosscaps and knots.

Clark, Bradd Evans (1978)

International Journal of Mathematics and Mathematical Sciences

Deloopings of the spaces of long embeddings

Keiichi Sakai (2014)

Fundamenta Mathematicae

The homotopy fiber of the inclusion from the long embedding space to the long immersion space is known to be an iterated based loop space (if the codimension is greater than two). In this paper we deloop the homotopy fiber to obtain the topological Stiefel manifold, combining results of Lashof and of Lees. We also give a delooping of the long embedding space, which can be regarded as a version of Morlet-Burghelea-Lashof's delooping of the diffeomorphism group of the disk relative to the boundary....

Elementary moves for higher dimensional knots

Dennis Roseman (2004)

Fundamenta Mathematicae

For smooth knottings of compact (not necessarily orientable) n-dimensional manifolds in n + 2 (or n + 2 ), we generalize the notion of knot moves to higher dimensions. This reproves and generalizes the Reidemeister moves of classical knot theory. We show that for any dimension there is a finite set of elementary isotopies, called moves, so that any isotopy is equivalent to a finite sequence of these moves.

Embedding products of graphs into Euclidean spaces

Mikhail Skopenkov (2003)

Fundamenta Mathematicae

For any collection of graphs G , . . . , G N we find the minimal dimension d such that the product G × . . . × G N is embeddable into d (see Theorem 1 below). In particular, we prove that (K₅)ⁿ and ( K 3 , 3 ) are not embeddable into 2 n , where K₅ and K 3 , 3 are the Kuratowski graphs. This is a solution of a problem of Menger from 1929. The idea of the proof is a reduction to a problem from so-called Ramsey link theory: we show that any embedding L k O S 2 n - 1 , where O is a vertex of (K₅)ⁿ, has a pair of linked (n-1)-spheres.

Currently displaying 21 – 40 of 149