{ "id": "math/0603429", "version": "v5", "published": "2006-03-17T14:11:55.000Z", "updated": "2008-01-15T17:38:23.000Z", "title": "A classification of smooth embeddings of 3-manifolds in 6-space", "authors": [ "A. Skopenkov" ], "comment": "32 pages, a link to http://www.springerlink.com added, to appear in Math. Zeit", "journal": "Math. Zeitschrift, 260:3 (2008) 647-672", "doi": "10.1007/s00209-007-0294-1", "categories": [ "math.GT", "math.AT" ], "abstract": "We work in the smooth category. If there are knotted embeddings S^n\\to R^m, which often happens for 2m<3n+4, then no concrete complete description of embeddings of n-manifolds into R^m up to isotopy was known, except for disjoint unions of spheres. Let N be a closed connected orientable 3-manifold. Our main result is the following description of the set Emb^6(N) of embeddings N\\to R^6 up to isotopy. The Whitney invariant W : Emb^6(N) \\to H_1(N;Z) is surjective. For each u \\in H_1(N;Z) the Kreck invariant \\eta_u : W^{-1}u \\to Z_{d(u)} is bijective, where d(u) is the divisibility of the projection of u to the free part of H_1(N;Z). The group Emb^6(S^3) is isomorphic to Z (Haefliger). This group acts on Emb^6(N) by embedded connected sum. It was proved that the orbit space of this action maps under W bijectively to H_1(N;Z) (by Vrabec and Haefliger's smoothing theory). The new part of our classification result is determination of the orbits of the action. E. g. for N=RP^3 the action is free, while for N=S^1\\times S^2 we construct explicitly an embedding f : N \\to R^6 such that for each knot l:S^3\\to R^6 the embedding f#l is isotopic to f. Our proof uses new approaches involving the Kreck modified surgery theory or the Boechat-Haefliger formula for smoothing obstruction.", "revisions": [ { "version": "v5", "updated": "2008-01-15T17:38:23.000Z" } ], "analyses": { "subjects": [ "57R40", "57R52" ], "keywords": [ "smooth embeddings", "classification", "concrete complete description", "kreck modified surgery theory", "disjoint unions" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 32, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math......3429S" } } }