Einstein Metrics and Equivariant Harmonic Maps: The Einstein Detection Principle

Abstract: We develop a new analytical framework for the local deformation theory of compact cohomogeneity-one Einstein metrics. The framework combines an intrinsic reformulation of the Einstein boundary-value problem with an auxiliary theory of equivariant harmonic maps and leads to what we call the Einstein Detection Principle. The auxiliary harmonic maps generate a rich variational, elliptic and spectral framework while introducing no additional Einstein degrees of freedom.