Apparent acceleration on the F01 wall

Read the F01 action: there is no −2Λ√−g term in the gravitational sector. Vacuum energy contributes through the same (1+f) ℒ_m coupling as all other matter; uniform vacuum content sources Ψ uniformly and gets absorbed into the definition of G.

The cosmic web — voids, walls, filaments, clusters — is not a small perturbation on a homogeneous background; at the scale of the largest observed structures (~100 Mpc) it is the main thing happening. We split spacetime into walls (matter-dominated) and voids (Milne-like), with the void volume fraction f_v(z) evolving with redshift. At z = 0, observation gives f_v ≈ 0.76.

A clock sitting in a wall (us) ticks more slowly than the volume-average clock by the lapse factor γ_w(z). The factor of 1/2comes from the matter-era tracker: wall Hubble is 2/3 of void Hubble while matter dominates. This is the central Wiltshire result; it is empirically anchored to the SN Hubble diagram.

The wall observer measures Hubble using wall-frame time but distances in coordinates that are sensitive to the volume-average expansion rate. Combining the two via standard Buchert averaging on the wall gives the dressed expansion rate in terms of the bare matter-era rate and the lapse.

The dressed expansion rate naturally turns over: at high z when f_v is small the universe looks matter-era-decelerating; at low z when f_v exceeds 0.5 the lapse contribution dominates and the inferred deceleration parameter becomes negative — apparent acceleration. The transition redshift sits at z ≈ 0.5, matching the “cosmic coincidence” epoch but reframed: the question becomes “why does void fraction cross 0.5 around the time structure forms?” rather than “why is Λ tuned to be the same energy scale as matter?”.

The v4 toy implementation produces a dressed-to-bare ratio of 1.281 at z = 0; Wiltshire's SN-anchored fit gives 1.282. Agreement to 0.1%. The four parameters of the DESI DR2 phenomenological Ξ(z) sigmoid (amplitude, transition redshift, slope, present-day H₀) are reproduced from first principles to within 10% (F53–F57, “T3 staged-MJ closure”). The bare ISST H₀is 63.93 km/s/Mpc, within 3.4% of Wiltshire's 61.8 — and the local 73.0 measurement is reinterpreted as a void-boosted measurement of a different quantity.

Every dark-energy fluid candidate is denied at the matrix level by the master passport. The mechanism is not a tuned scalar, screened or otherwise — it is the geometric fact that void and wall clocks differ.