Vanishing spatial shell coefficient

The spatial cutoff derivative coefficient tends to zero as its radius increases through the natural numbers.

theorem ESS.buShortShellCoeff_tendsto_zero (scale c₁ : ℝ) : Filter.Tendsto (fun (n : ℕ) => buShortShellCoeff scale (↑n + 1) c₁) Filter.atTop (nhds 0)

The shell error coefficient vanishes along radii n + 1.