2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84531A particular problem about special kind of two light pulses propagation has been considered in cases of inertial motion, constant homogeneous gravitation field and progressive non-inertial motion with constant acceleration. A contradiction between the causality principle and relativity theory has been revealed.4 pagesGeneral Physicstext