Local Actuality and Reciprocal Retardation: A Lorentz-Covariant Present-Record Formalism for FCLET

Observation across astronomical distance is a present physical interaction with a retarded causal record. A telescope directed toward a system one thousand light-years away registers radiation emitted one thousand years earlier; the telescope never accesses the spacelike-separated local state of that system. When two stationary observers separated by one thousand light-years perform the same observation at equal coordinate time in a selected inertial frame, each receives a record of the other’s state from one thousand years earlier. Their observation is reciprocal, their records are retarded, and their respective reception events remain locally actual. This paper establishes the Lorentz-covariant present-record formalism of FCLET. It defines event–record non-identity, event-local physical state, causal record support, retarded registration, worldline-local succession, reciprocal retardation, causal partial order, foliation independence, causal-diamond capacity, and the FCLET latency scalar. The formalism distinguishes invariant causal structure from frame-dependent distant simultaneity and replaces the expression “both systems are universally in 2026” with its exact relativistic content: both possess locally instantiated states at their respective reception events, while equality of their coordinate labels belongs to a selected synchronization frame. The paper proves the Reciprocal Retardation Lemma, the Causal Record Accessibility Theorem, the Local Actuality Proposition, the Capacity–Latency Monotonicity Proposition, and the Relativistic Admissibility Theorem. Finite record capacity is formulated over the invariant causal diamond . The coordinate-dependent FCLET rate law is completed by the scalar duration relation where is metric proper time and is the dimensionless FCLET latency field. The positive latency factor preserves timelike ordering and the conformal metric preserves the null-cone structure. The resulting architecture fixes the exact connection between Article 103 and relativistic physics: a completed event and its present record are physically distinct; information from the event reaches later receivers through causal carriers; local actuality requires no preferred foliation; and finite-capacity dynamics enter through a covariant latency sector with measurable clock and record-channel consequences. Reciprocal past-light observation therefore provides the causal foundation of the FCLET present-record universe.