Linking requires D = 3 (Alexander duality) Alexander duality shows that S^D admits non-trivial circle linking iff the reduced cohomology H̃^{D-2}(S¹) is nontrivial, which holds precisely for D = 3. This is proved by alexander_duality_circle_linking and yields linking_requires_D3, ensuring stable ledger conservation only in three dimensions.
8-tick = 2^D forces D = 3 The eight-tick cycle is defined as EightTickFromDimension D = 2^D. The theorem eight_tick_forces_D3 proves that equality to eight_tick forces D = 3, since 2^D = 8 holds solely for D = 3.
Cl_3 spinor structure Only D = 3 produces 2-component complex spinors with Cl₃ ≅ M₂(ℂ) and Spin(3) ≅ SU(2). This is characterized by D3_has_spinor_structure together with spinorDimension 3 = 2.
Cited Lean anchors The derivation rests on the verbatim theorems eight_tick_forces_D3, linking_requires_D3, alexander_duality_circle_linking and D3_has_spinor_structure.