Emergence of FLRW Cosmology from Discrete Horizon Layering

We present a kinematic reconstruction in which an FLRW interior arises asthe maximally symmetric continuum description associated with a discretelygrowing, spherically symmetric horizon. The horizon is treated not merely asa classical causal boundary but as a holographic data surface from which aneffective interior geometry is reconstructed. Rather than solving the bulk Ein-stein equations for a prescribed stress–energy source, we introduce an explicithorizon-update rule in which the Schwarzschild radius increases in fixed Planck-scale steps, together with an information-weighted mapping from the discreteupdate index to a continuous comoving radial coordinate. As the horizon areagrows, the number of available degrees of freedom increases, while the radial res-olution assigned to successive layers decreases accordingly. Summation of theseinformation-limited increments yields a finite reconstructed comoving domainand a smooth isotropic continuum limit. Within this explicitly defined recon-struction class, imposing an operational stacking convention that identifies arealradius with accumulated proper radial depth selects the spatially flat represen-tative of the FLRW family. The resulting interior metric exhibits a coastingexpansion law with H(t) ≃ 1/t, arising from the synchronization between dis-crete horizon updates and a postulated stretched-horizon proper-time parameter.The construction is intentionally agnostic to the detailed horizon realizationat the level employed here, relying only on spherical symmetry, the horizonarea–information relation, and null-synchronized layering to define the emergentinterior kinematics.