English
The L2-operator norm of a matrix equals the operator norm of the corresponding Euclidean endomorphism.
Русский
L2-операторная норма матрицы равна операторной норме соответствующего унитарного отображения Евклидова пространства.
LaTeX
$$$\\|A\\| = \\|(toEuclideanLin(𝕜)(m)(n)).trans toContinuousLinearMap A\\|$$$
Lean4
/-- An auxiliary definition used only to construct the true `NormedRing` (and `Metric`) structure
provided by `Matrix.instMetricSpaceL2Op` and `Matrix.instNormedRingL2Op`. -/
def l2OpNormedRingAux : NormedRing (Matrix n n 𝕜) :=
@NormedRing.induced ((Matrix n n 𝕜) ≃⋆ₐ[𝕜] (EuclideanSpace 𝕜 n →L[𝕜] EuclideanSpace 𝕜 n)) _ _ _ _
ContinuousLinearMap.toNormedRing _ _ toEuclideanCLM.injective