Chapter 8: Contract with Parts~II–VIII: The Cosmic Stack API

Part I is now complete. Seven chapters have earned the base vocabulary of Book V: time as arc length on τ¹, three temporal epochs, initial conditions, the photon ontology, operational distance, redshift as refinement drift, the distance ladder as readout calibration, and the CMB and CνB as constraint surfaces. No gravity has been invoked. No thermodynamics has been assumed. No cosmological model has been fitted. Everything earned so far follows from the base circle τ¹ and the sector couplings inherited from Book IV.

The stack construction that follows pastes sector-wise data into a globally coherent cosmic structure. This pasting is licensed by Global Cartesian Gluing (Book III, III.T50), which guarantees that local sector constructions compose into a consistent whole.

This chapter records what has been earned (§), what remains to be earned (§), and assembles both into a compact interface specification—the Cosmic Stack API—that governs the contract between Part I and the rest of the book (§). The chapter closes with a summary table of all definitions and theorems earned in Part I (§).