a

Many authors have questioned the use of the index of the vector field, and of the Chern classes, if the underlying space becomes singular. This book discusses their explorations within the framework of the obstruction theory and the Chern-Weil theory.

The main subjects of the Siegen Topology Symposium are reflected in this collection of 16 research and expository papers. They center around differential topology and, more specifically, around linking phenomena in 3, 4 and higher dimensions, tangent fields, immersions and other vector bundle morphisms. Manifold categories, K-theory and group actions are also discussed.

This volume reflects the work of the Brazilian topology community. It also contains the work of some topologists who either collaborate or interact with a Brazilian topologist. Most of the work has been done in algebraic and geometric topology.