theorem
proved
term proof
alexander_duality_circle_linking
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formal statement (Lean)
145theorem alexander_duality_circle_linking (D : ℕ) :
146 SphereAdmitsCircleLinking D ↔ D = 3 := by
proof body
Term-mode proof.
147 unfold SphereAdmitsCircleLinking
148 rw [circle_reduced_cohomology_iff]
149 constructor <;> intro h <;> omega
150
151/-! ## Derived Facts -/
152
153/-- D = 3 admits circle linking (forward direction). -/