Inner Automorphisms #
This file ports the upstream monlib4 unitary inner-automorphism interface. In
current Mathlib the general star-algebra automorphism by unitary conjugation is
available as Unitary.conjStarAlgAut; the declarations here keep monlib4's
names for the matrix-algebra specialization and its trace, spectrum, and
Hermitian-preservation lemmas.
The star-algebra automorphism given by conjugation with a unitary element.
Equations
- unitary.innerAutStarAlg K a = (Unitary.conjStarAlgAut K R) a
Instances For
Build a unitary element of a dependent function type from pointwise unitaries.
Equations
- unitary.pi U = โจfun (i : k) => โ(U i), โฏโฉ
Instances For
The star-algebra automorphism x โฆ U * x * Uโปยน.
Equations
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The unitary inner automorphism as a linear map.
Equations
Instances For
A matrix is Hermitian iff its image under a unitary inner automorphism is Hermitian.
A unitary inner automorphism preserves positive semidefinite matrices.
A unitary inner automorphism preserves positive definite matrices.
Every star-algebra equivalence of Mโ is implemented by a unitary conjugation.
A unitary matrix implementing a star-algebra equivalence of full matrix algebras.
Equations
- f.ofMatrixUnitary = (fun (U : โฅ(Matrix.unitaryGroup n ๐)) (x : Matrix.innerAutStarAlg U = f) => U) (Classical.choose โฏ) โฏ
Instances For
Spectral theorem in Monlib's inner-automorphism notation.
Entrywise conjugate of a unitary matrix as a unitary.
Equations
- Matrix.unitaryGroup.conj U = โจ(โU).conj, โฏโฉ
Instances For
The Kronecker product of two unitary matrices as a unitary matrix.
Equations
- Matrix.unitaryGroup.kronecker Uโ Uโ = โจMatrix.kroneckerMap (fun (x1 x2 : ๐) => x1 * x2) โUโ โUโ, โฏโฉ