2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149791For the Calabi-Yau threefolds $X$ constructed by C. Schoen as fiber products of generic rational elliptic surfaces, we show that the action of the automorphism group of $X$ on the Kähler cone of $X$ has a rationally polyhedral fundamental domain. The second author has conjectured that this statement will hold in general, the example presented here being the first non-trivial case in which the statement has been checked. The conjecture was motivated by the desire to use a construction of E. Looijenga to compactify certain moduli spaces which arise in the study of conformal field theory and ``mirror symmetry.''8 pp., AmS-TeX v.2Algebraic Geometrytext