  It was demonstrated recently that there is an upper bound of the Chern-Simons
coupling of the five-dimensional Einstein-Maxwell theory, beyond which the
electrically charged AdS_2 \times S^3 vacuum solution becomes unstable. We
generalize the result to a general class of gravity theories involving
Chern-Simons and/or transgression terms and find their upper bounds for
stability. We show that supergravities with AdS \times Sphere vacua satisfy the
bounds.

High Energy Physics - Theory