2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/225128The foundations of Einstein's first (1907) principle of equivalence are explored and their consequences are stated in terms of invariance under generalized Lorentz transformations, first explored by Hessenberg.32 pages ; 3 figures ; Hessenberg Appendix properly included and figures modifiedHistory and Philosophy of PhysicsGeneral Relativity and Quantum Cosmologytext