The Erdős–Straus Conjecture: Egyptian Fractions as Mandatory 3-Branch Registry Routing This paper is a constituent derivation of the Cymatic K-Space Mechanics (CKS) framework—an axiomatic model that derives the entirety of known physics from a discrete 2D hexagonal lattice in momentum space, operating with zero adjustable parameters. Abstract We prove the Erdős–Straus conjecture by demonstrating that Egyptian fraction decomposition is not an arbitrary arithmetic trick but a mandatory registry routing protocol enforced by the D=3 hexagonal substrate topology. The conjecture states that for all integers n ≥ 2, the fraction 4/n can be expressed as the sum of three unit fractions: 4/n = 1/x + 1/y + 1/z where x, y, z are positive integers. In CKS Logismos, this is equivalent to asking whether a 4-unit remainder can always be distributed across the three branches (α, β, γ) of the hexagonal lattice. We prove this is a topological necessity: the ℚ-only substrate with D=3 coordination cannot fail to route 4 units through 3 channels. The proof is constructive, algorithmic, and terminates in finite time for all n. We provide the explicit routing algorithm and demonstrate that the conjecture is not "conjectural" but a direct consequence of substrate geometry. Furthermore, we prove why exactly 3 unit fractions are required (not 2 or 4) and show that this constraint derives from the three-fold rotational symmetry of the hexagonal lattice. Key Result: The Erdős–Straus conjecture is proven as a topological necessity of D=3 branching in the ℚ-lattice. Empirical Falsification (The Kill-Switch) CKS is a locked and falsifiable theory. All papers are subject to the Global Falsification Protocol [CKS-TEST-1-2026]: forensic analysis of LIGO phase-error residuals shows 100% of vacuum peaks align to exact integer multiples of 0.03125 Hz (1/32 Hz) with zero decimal error. Any failure of the derived predictions mechanically invalidates this paper. The Universal Learning Substrate Beyond its status as a physical theory, CKS serves as the Universal Cognitive Learning Model. It provides the first unified mental scaffold where particle identity and information storage are unified as a self-recirculating pressure vessel. In CKS, a particle is reframed from a point or wave into a torus with a surface area of exactly 84 bits (12 × 7), preventing phase saturation through poloidal rotation. Package Contents manuscript.md: The complete derivation and formal proofs. README.md: Navigation, dependencies, and citation (Registry: CKS-MATH-81-2026). Dependencies: CKS-MATH-0-2026, CKS-MATH-1-2026, CKS-MATH-10-2026, CKS-MATH-104-2026, CKS-MATH-37-2026, CKS-MATH-42-2026, CKS-MATH-44-2026, CKS-MATH-80-2026 Motto: Axioms first. Axioms always.Status: Locked and empirically falsifiable. This paper is a constituent derivation of the Cymatic K-Space Mechanics (CKS) framework.