The aim of this book is to study harmonic maps, minimal and parallel
mean curvature immersions in the presence of symmetry. In several
instances, the latter permits reduction of the original elliptic
variational problem to the qualitative study of certain ordinary
differential equations: the authors' primary objective is to provide
representative examples to illustrate these reduction methods and their
associated analysis with geometric and topological applications.
The material covered by the book displays a solid interplay involving
geometry, analysis and topology: in particular, it includes a basic
presentation of 1-cohomogeneous equivariant differential geometry and of
the theory of harmonic maps between spheres.