This paper develops the electromagnetic routing layer within the Length–Mass Reduction (LMR) framework. Building on the lattice grammar, persistence conditions, and primitive configurations established in Papers I–III, it identifies the structural conditions under which a persistent but asymmetric configuration becomes externally legible. Electromagnetic projections arise as admissible projections of lattice structure through an open half-fold, rather than as forces, fields, or carriers. The exposition remains predynamical. No equations of motion, energetic assumptions, or field postulates are introduced. Electromagnetic behavior is presented as an external routing grammar governed by admissibility gradients and projection constraints. This treatment prepares the ground for the normalization and inflow grammar developed in Paper V. Any dynamical interpretation is deferred to observer-side overlays and does not enter the predynamical LMR framework.
Jacob Rollins (Fri,) studied this question.