2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/134807In this brief note, we reconsider the problem of finding Euclidean wormhole solutions to maximal supergravity in d dimensions. We find that such solutions exists for all d less than or equal to 9. However, we argue that, in toroidally-compactified string theories, these saddle points never contribute to the path integral because of a tension with U-duality.10 pages, LaTeX2e with utarticle.clsHigh Energy Physics - Theorytext