Link Groups of 4-manifolds
نویسنده
چکیده
We introduce the notion of a flexible 2 -cell and use it to define invariants – link groups – of 4 -manifolds. Flexible cells combine some features of both surfaces and handlebodies, therefore the link group λ(M) measures certain aspects of the handle structure of a 4 -manifold M . This group is a quotient of the fundamental group, and we construct examples of manifolds M with π1(M) 6= λ(M) . More detailed information is contained in a two-parameter family of link groups λi,j(M) . A generalization of the Milnor group is developed to formulate an obstruction to embeddability of flexible cells into 4 -space.
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The notion of a Bing cell is introduced, and it is used to define invariants, link groups, of 4-manifolds. Bing cells combine some features of both surfaces and 4-dimensional handlebodies, and the link group λ(M) measures certain aspects of the handle structure of a 4-manifold M . This group is a quotient of the fundamental group, and examples of manifolds are given with π1(M) 6= λ(M). The main...
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