Isometric invariance of the positive-frequency kernel in generalized FRW-like spacetimes
arXiv:gr-qc/9812048
Abstract
Klein-Gordon equation with minimal coupling in FRW-like spacetimes with compact but not necessarily isotropic neither homogeneous space sections. Beside exceptional cases, the kernel is invariant under continuous isometries.
Latex file, 7 pages, Contribution to ERES98 held at Salamanca, Spain