OAI/Analysis/KadisonSimilarity/Derivation/CStarRowSquare.lean

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The positive row square and its native C-star matrix norm.

  1. theorem OAI.KadisonSimilarity.norm_rowSquare_le line 16

    Source documentation

    The sum of xx* of a row has norm bounded by its matrix norm squared.

    theorem norm_rowSquare_le {n : ℕ} (X : Matrix (Fin 1) (Fin n) A) :
        ‖∑ j : Fin n, X 0 j * star (X 0 j)‖ ≤ ‖CStarMatrix.ofMatrix X‖ ^ 2 := by
    …
  2. theorem OAI.KadisonSimilarity.positiveFunctional_rowSquare_le line 49

    Source documentation

    A positive functional of mass at most one is bounded on the row square.

    theorem positiveFunctional_rowSquare_le (f : A →ₚ[ℂ] ℂ) (hf : (f 1).re ≤ 1)
        {n : ℕ} (X : Matrix (Fin 1) (Fin n) A) :
        ∑ j : Fin n, (f (X 0 j * star (X 0 j))).re ≤ ‖CStarMatrix.ofMatrix X‖ ^ 2 := by
    …