2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/125148We study four-dimensional compactifications of type II superstrings on Calabi-Yau spaces in the hybrid formalism. Chiral and twisted-chiral interactions are rederived, which involve the coupling of the compactification moduli to two powers of the Weyl-tensor and of the derivative of the universal tensor field-strength. We review the formalism and provide details of some of its technicalities.v1: 18 pages, harvmac. v2: v2: 32 pages, substantially expanded version to appear in the ICMP 2006 proceedings. LaTeX formatHigh Energy Physics - Theorytext