def oscillationEnergy (H : Fin N → ℝ) (ξ : Fin N → ℝ) : ℝ := (1 / 2 : ℝ) * ∑ n : Fin N, H n * ξ n ^ 2
thesis/CESProofs/Dynamics/Defs.lean:205
Core definitions for the Lean formalization of Paper 3: