In a remarkably short time, the field of inequality problems has seen
considerable development in mathematics and theoretical mechanics.
Applied mechanics and the engineering sciences have also benefitted from
these developments in that open problems have been treated and entirely
new classes of problems have been formulated and solved. This book is an
outgrowth of seven years of seminars and courses on inequality problems
in mechanics for a variety of audiences in the Technical University of
Aachen, the Aristotle University of Thessaloniki, the University of
Hamburg and the Technical University of Milan. The book is intended for
a variety of readers, mathematicians and engineers alike, as is detailed
in the Guidelines for the Reader. It goes without saying that the work
of G. Fichera, J. L. Lions, G. Maier, J. J. Moreau in originating and
developing the theory of inequality problems has considerably influenced
the present book. I also wish to acknowledge the helpful comments
received from C. Bisbos, J. Haslinger, B. Kawohl, H. Matthies, H. O.
May, D. Talaslidis and B. Werner. Credit is also due to G. Kyriakopoulos
and T. Mandopoulou for their exceptionally diligent work in the
preparation of the fmal figures. Many thanks are also due to T. Finnegan
and J. Gateley for their friendly assistance from the linguistic
standpoint. I would also like to thank my editors in Birkhiiuser Verlag
for their cooperation, and all those who helped in the preparation of
the manuscript.
