Phase‑Coordination Series Conventions: Normative Interoperability Reference for Cycle/Phase/Window/Tick Semantics in the Timeverse Stack

Phase-Coordination Series Conventions defines the canonical interoperability rules used across the Timeverse / Phase-Coordination document series. It fixes: Protocol conventions (t0, T_cycle) and a strict requirement that computations use an autonomous, monotone arithmetic time variable (no leap seconds). UTC/RFC3339 timestamps are permitted for UI/logging only and must be mapped via an explicit policy. The canonical cycle index n(t) and normalized phase φ(t) ∈ [0,1) ≅ S¹, including a negative-safe modulo convention. Wrap-around-safe circular distance on S¹ and phase acceptance windows with a consistent half-width tolerance ΔΦ, plus the window-duration mapping. Human-facing displays (HS° degrees and a 12-segment HS index) as derived representations of the same phase point. A normative fixed-point “ticks” encoding (integer ticks per cycle) for window membership and verification, avoiding floating-point boundary ambiguity. Requirements for a convention_id that binds (t0, T_cycle), the arithmetic time policy, tick resolution, and boundary semantics. This document is intended to be cited as the normative reference for phase/cycle/window/tick semantics by higher-layer specs (e.g., Q-Address, security profiles, bootstrapping, UI/AI layers). DOI: https://doi.org/10.5281/zenodo.18068999