2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54884We extend recent work by Elizalde et al. to incorporate curvatures which are not small and backgrounds which are not just $S^2\times R^2, S^1\times S^1 \times R^2$. Some possible problems in their paper is also pointed out.standard LaTeX, 4 pagesHigh Energy Physics - TheoryGeneral Relativity and Quantum Cosmologytext