Problems linking the shape of a domain or the coefficients of an
elliptic operator to the sequence of its eigenvalues are among the most
fascinating of mathematical analysis. In this book, we focus on extremal
problems. For instance, we look for a domain which minimizes or
maximizes a given eigenvalue of the Laplace operator with various
boundary conditions and various geometric constraints. We also consider
the case of functions of eigenvalues. We investigate similar questions
for other elliptic operators, such as the Schrödinger operator, non
homogeneous membranes, or the bi-Laplacian, and we look at optimal
composites and optimal insulation problems in terms of eigenvalues.
Providing also a self-contained presentation of classical isoperimetric
inequalities for eigenvalues and 30 open problems, this book will be
useful for pure and applied mathematicians, particularly those
interested in partial differential equations, the calculus of
variations, differential geometry, or spectral theory.