Route Residue as the Origin of Transparent Spatiality A Canonical Clarification within the Ambient Era

Abstract This document provides a canonical clarification of route residue as the foundational substrate of transparent spatial interfaces. Originally formulated within the chromatic navigation layer (AP₁), route residue is here reinterpreted as the primary anchoring mechanism that makes transparency, spatial navigation, and depth-based interfaces thermodynamically viable. The clarification resolves a central question of the Ambient Era: why spatial interfaces collapse into surface scrolling when residue is absent, and why transparency becomes possible only after residue emerges as the carrier of navigation, memory, and identity. This note establishes route residue not as a feature of navigation systems, but as the origin condition of transparent spatiality itself. It situates route residue precisely within the canonical evolutionary sequence AP₁ → AP₂ → TP₁, and positions it in structural alignment with Reversible Residue (RR₁), Residue Identity (RID-1), the Residue Anchoring Law (RAL-1), and the Residue–Transparency Law (RTL-1).