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LeanPool.EscauriazaSereginSverak.Linear.BUShortAverageExponents

Exponents under short-time rescaling #

The spatial growth exponent scales quadratically, while the normal Gaussian decay retains an inverse dyadic time scale.

The squared Euclidean norm in three coordinates is the sum of the three coordinate squares (lem:bu-small-time).

theorem ESS.bu_short_average_normal_tail_le (scale β δ d : ℝ) (Y : CKN.Foundation.Parabolic.Vec3) (hscale : 0 < scale) (hβ : 0 < β) (hδ : 0 < δ) (hδd : δ ≤ d) :
have t := scale ^ 2 * δ / 2; have X := scale • Y; Real.exp (-(β * X 2 ^ 2 / (12 * t))) ≤ Real.exp (-(β * Y 2 ^ 2 / (12 * d)))

The physical Gaussian normal tail dominates the dyadic normal tail after short-time rescaling (lem:bu-small-time).