The Position of Echo-Feedback Cognitive φ-Substrate (PEFCφS): A Four-Layer Architecture for the Harmonic Nexus Core Framework

We present a unified theoretical architecture — the Position of Echo-Feedback Cognitive φ-Substrate (PEFCφS) — that organises the Harmonic Nexus Core (HNC) framework into a four-layer stack: substrate, dynamics, forcing, and output. The substrate is anchored by the φ² Coherence Bridge, connecting the seed frequency to the hydrogen 21 cm hyperfine line. Aureon Institute, 2026.