2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/107012Fluctuation Theorems are statements about the entropy of systems far from thermal equilibrium. In this Letter relativistic Fluctuation Theorems for Brownian motion are presented and proven. Though there is a known discretization dilemma leading to a certain class of Brownian processes, the Fluctuation Theorems are shown to cover the entire class, and to determine the physical process within this class. In the general-relativistic case the heat responsible for entropy production is the exchanged 4-momentum projected on the local time axis of the heat bath.4 pages, 1 figureStatistical Mechanicstext