Chapter 20: Dimension and the Fibration Preview

The ABCD chart assigns four coordinates to every object. Are these coordinates independent? Could the universe be described by fewer? This chapter proves that dim_τ = 4: the four ABCD coordinates form four pairwise independent refinement rays, and no three coordinates suffice to address all objects. We then preview the fibration structure: the 1+3 split corresponds to base τ¹ (coordinates D, A) and fiber T² (coordinates B, C), foreshadowing the central geometric object τ³ = τ¹ ×_f T² that will dominate the rest of the Panta Rhei series.