Order properties of Ring.inverse in C⋆-algebras #
This file shows that Ring.inverse is convex on strictly positive operators.
Main declarations #
convexOn_ringInverse:Ring.inverseis convex on strictly positive operators, i.e. the inverse is operator convex.
theorem
CStarAlgebra.convexOn_ringInverse
{A : Type u_1}
[CStarAlgebra A]
[PartialOrder A]
[StarOrderedRing A]
:
ConvexOn ℝ {a : A | IsStrictlyPositive a} Ring.inverse
theorem
CStarAlgebra.convexOn_ringInverse_algebraMap_add
{A : Type u_1}
[CStarAlgebra A]
[PartialOrder A]
[StarOrderedRing A]
{t : ℝ}
(ht : 0 < t)
:
ConvexOn ℝ (Set.Ici 0) fun (x : A) => Ring.inverse ((algebraMap ℝ A) t + x)