This book has been written in a frankly partisian spirit-we believe that
singularity theory offers an extremely useful approach to bifurcation
prob- lems and we hope to convert the reader to this view. In this
preface we will discuss what we feel are the strengths of the
singularity theory approach. This discussion then Ieads naturally into a
discussion of the contents of the book and the prerequisites for reading
it. Let us emphasize that our principal contribution in this area has
been to apply pre-existing techniques from singularity theory,
especially unfolding theory and classification theory, to bifurcation
problems. Many ofthe ideas in this part of singularity theory were
originally proposed by Rene Thom; the subject was then developed
rigorously by John Matherand extended by V. I. Arnold. In applying this
material to bifurcation problems, we were greatly encouraged by how weil
the mathematical ideas of singularity theory meshed with the questions
addressed by bifurcation theory. Concerning our title, Singularities and
Groups in Bifurcation Theory, it should be mentioned that the present
text is the first volume in a two-volume sequence. In this volume our
emphasis is on singularity theory, with group theory playing a
subordinate role. In Volume II the emphasis will be more balanced.
Having made these remarks, Iet us set the context for the discussion of
the strengths of the singularity theory approach to bifurcation. As we
use the term, bifurcation theory is the study of equations with multiple
solutions.