Thijs de Kok

A Pontryagin class obstruction for purely electric and purely magnetic Weyl curvature tensors

Abstract Do all manifolds that admit Lorentzian metrics also admit such metrics that have a purely electric (PE) or purely magnetic (PM) Weyl curvature tensor? To (partially) answer this question, we show that for all algebraic curvature tensors on a 4 k -dimensional scalar produ...