We propose and partially establish a unified theory — the Sakai stratification of PCF transcendence — organizing the arithmetic complexity of constants arising from polynomial continued fractions (PCFs) according to the Sakai surface type of their isomonodromic deformation. The central object is the connection coefficient C of the Borel-transformed generating function G (s) = Σ Qₙ sⁿ/ (dn) !, a transcendence candidate that the companion Edge–Borel Radius (EBR) series identifies as the dominant singularity amplitude. Our main claim is a two-tier master conjecture: for degree-2 PCFs, the sign of the balanced discriminant Δ = β₁² − 4β₂β₀ determines whether C is elementary or a genuine transcendental period of the governing Sakai connection, a dichotomy now established at the STRUCTURAL level across 30 families; for degree d ≥ 3, the same surface-theoretic prediction holds at the CONJECTURED level pending the higher-degree connection analysis. The theory unifies a corpus of approximately 30 deposits spanning Lean 4 / Mathlib formalization, Borel–Galois analysis, isomonodromy theory, and arithmetic computation into a single conceptual framework. Three principal open problems — an explicit period-integral representation of C, the d ≥ 3 connection problem, and a functoriality theorem for the bridge map — define the frontier.
Papanokechi (Mon,) studied this question.