V.D22 — Sigma-Now Hypersurface

The now-hypersurface Sigma_now is the set of all configurations in tau^3 at the current refinement depth n_*: Sigma_now = {x in tau^3 : depth(x) = n_*} = {alpha_{n_*}} x T^2_{n_*}, a codimension-1 slice that is topologically T^2 (compact and spacelike in the chart-level readout).