OAI/Geometry/EinsteinFour/Spectral.lean

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Spectral bounds for a Weyl block

Only the three real eigenvalues and their trace and norm identities are used. The minimum eigenvalue is -x, and the Hilbert--Schmidt norm is sqrt 6 * v.

  1. theorem OAI.PositiveEinsteinFour.weyl_eigenvalue_norm_bounds line 17

    Source documentation

    The least eigenvalue of a real trace-free three-dimensional block controls its normalized norm, including the zero block. This is the bound v ≤ x ≤ 2v from Section 2 of the manuscript.

    theorem weyl_eigenvalue_norm_bounds
        (v x s t : ℝ) (hv : 0 ≤ v)
        (htrace : -x + s + t = 0)
        (hnorm : x ^ 2 + s ^ 2 + t ^ 2 = 6 * v ^ 2)
        (hs : -x ≤ s) (ht : -x ≤ t) :
        v ≤ x ∧ x ≤ 2 * v := by
    …
  2. theorem OAI.PositiveEinsteinFour.weyl_norm_sum_lt_two line 34

    Source documentation

    Sectional positivity expressed by the two minimum eigenvalues implies the strict sum bound for the normalized Weyl norms.

    theorem weyl_norm_sum_lt_two
        (v b x y : ℝ) (hvx : v ≤ x) (hby : b ≤ y) (hpositive : x + y < 2) :
        v + b < 2 := by
    …