V81: Dark Energy as a Space-Update Floor — Log Mapping Improves H(z) Beyond ΛCDM

Following V80, which demonstrated that dark matter phenomena can be explained as the accumulation of space-update delays (Σ-dynamics), we address dark energy (DE) within the same framework. We avoid assumptions about acceleration or scalar fields and confront observations directly at the level of the Hubble parameter H(z). Using BAO and SNe Ia data, we test four mapping functions from space-update rate ν to H(z). We show that: A square-root mapping reproduces ΛCDM exactly (Δχ² = 0), demonstrating structural equivalence between the space-update floor (ν_floor) and the cosmological constant (Λ). A logarithmic mapping yields statistically significant improvement (Δχ² = −8.72) over ΛCDM without introducing new fields or particles. Linear and tanh mappings are strongly rejected, providing discriminating power within the mapping family. We derive a falsifiable prediction for the redshift evolution of the effective equation-of-state parameter w(z). The model predicts w ≈ −1 at low redshift (consistent with current data) and a modest deviation w > −1 at z ∼ 1, with a maximum Δw ≈ +0.06 to +0.08. This deviation is within reach of upcoming surveys (Euclid, DESI, Rubin LSST) and constitutes a clear observational test. Combined with V80 (DM = Σ accumulation), this work completes the space-update interpretation of both dark sectors: dark matter is where space remembers; dark energy is what space costs. One-sentence thesis: Dark energy can be reinterpreted as the background cost of maintaining space itself—the space-update floor ν_floor—and a logarithmic response to this floor outperforms ΛCDM while yielding testable predictions.