Topological degree for elliptic operators in unbounded cylinders
Jean–François Collet, V. A. Volpert, Aizik Volpert · Advances in Differential Equations · 1999
Semilinear elliptic operators in unbounded cylinders are considered. It is shown that under some conditions the operators are Fredholm and proper. A topological degree for these operators is defined and shown to be unique. The results are applied to operators describing traveling waves.