title: Local invariants vanishing on stationary horizons: a diagnostic for locating black holes.
abstract: Inspired by the example of Abdelqader and Lake for the Kerr metric, we construct local scalar polynomial curvature invariants that vanish on the horizon of any stationary black hole: the squared norms of the wedge products of n linearly independent gradients of scalar polynomial curvature invariants, where n is the local cohomogeneity of the spacetime.
authors.affiliation: Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
authors.forename: Don N
authors.initials: DN
authors.lastname: Page
authors.affiliation: Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G 2E1, Canada.
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Shoom