Stefan Bechtluft-Sachs

TENSION FIELD AND INDEX FORM OF ENERGY-TYPE FUNCTIONALS

We derive variational formulae for natural first order energy function- als and obtain criteria for the stability of isometric immersions. This generalizes known results for the classical energy, the p-energy and the exponential energy

The local defect index up to finite ambiguity

Abstract The rational Hopf invariant of the primary obstruction to a nowhere vanishing section in a vectorbundle is computed in terms of characteristic classes. This leads to a local rigidity result on the local defect index of a map.

An integral formula for the maslov-index of a symplectic path

The Maslov index of a not necessarily closed path M in the symplectic group Sp(2n) is expressed by an integral formula. We have an explicit formula for the integrand which is a rational 1-form on Sp(2n).