Link manifolds.

Link Groups of 4-manifolds

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) . M...

Link Manifolds and Periodicity 571

Dual Decompositions of 4-manifolds Ii: Linear Link Invariants

This paper continues the study of decompositions of a smooth 4-manifold into two handlebodies with handles of index ≤ 2. Part I gave existence results in terms of spines and chain complexes over the fundamental group of the ambient manifold. Here we exploit the fact that one side of a decomposition frequently has larger fundamental group to define algebraic-topological invariants. The main theo...

Triangulating 3-manifolds Using 5 Vertex Link Types

WE SHOW that a closed orientable 3-manifold can be triangulated in a simple way locally. There are 5 triangulations of S2 with the property that every such manifold has a triangulation in which the link of each vertex is one of these 5 link types. This triangulation is obtained from a paving of the manifold by cubes. In this paving, the order of every edge is 3,4 or 5. Denoting the union of the...

On some generalized recurrent manifolds

‎The object of the present paper is to introduce and study a type of non-flat semi-Riemannian manifolds‎, ‎called‎, ‎super generalized recurrent manifolds which generalizes both the notion of hyper generalized recurrent manifolds [‎A.A‎. ‎Shaikh and A‎. ‎Patra‎, On a generalized class of recurrent manifolds‎, Arch‎. ‎Math‎. ‎(Brno) 46 (2010) 71--78‎.] and weakly generalized recurrent manifolds ...