Causal Memory Gravity I: Cosmological Baseline and Reduced Almost-Λ Dynamics

Causal Memory Gravity I presents the cosmological baseline of the CMG framework and develops the reduced almost-Λ dynamics used as the starting point for later observational tests. The paper formulates the effective causal-memory gravitational sector, in which a retarded nonlocal curvature response modifies General Relativity only in the infrared regime. It introduces the main cosmological parameters, stability conditions, GR recovery limits, and the reduced background dynamics needed to compare CMG with standard ΛCDM. The document also separates the controlled near-GR baseline from stronger claims that require full perturbation, DESI, CMB, or nonlinear screening analyses. It serves as the primary cosmological foundation paper of the CMG series, linking the nonlocal memory action to late-time cosmic expansion and structure-growth phenomenology. For the full CMG corpus, theory map, and related materials, visit: https://cmg.beogradpc.com/