2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/59861We formulate the modularity conjecture for rigid Calabi-Yau threefolds defined over the field Q of rational numbers. We establish the modularity for the rigid Calabi-Yau threefold arising from the root lattice A_3. Our proof is based on geometric analysis.16 pages, latex, minor corrections. references addedAlgebraic GeometryNumber Theory14J32,11F11, 11F80, 11G18, 14K30text