Inner automorphisms #
This file defines the inner automorphism of a unitary matrix U
as U x Uโปยน
and proves that any star-algebraic automorphism on Mโ(โ)
is an inner automorphism.
Alias of RCLike.zero_le_real
.
Equations
- unitary.innerAutStarAlg K a = StarAlgEquiv.ofAlgEquiv (Algebra.autInner โa) โฏ
Instances For
Equations
- instCoeTCSubtypeMemSubmonoidUnitary_monlib R = { coe := fun (x : โฅ(unitary R)) => โx }
Equations
- unitary.pi U = โจfun (i : k) => โ(U i), โฏโฉ
Instances For
given a unitary $U$, we have the inner algebraic automorphism, given by $x \mapsto UxU^*$ with its inverse given by $x \mapsto U^* x U$
Equations
Instances For
inner automorphism (matrix.innerAut_star_alg
), but as a linear map
Equations
- Matrix.innerAut U = (Matrix.innerAutStarAlg U).toLinearMap
Instances For
the spectrum of $U x U^*$ for any unitary $U$ is equal to the spectrum of $x$
the spectrum of a linear map $x$ equals the spectrum of
$f_U^{-1} x f_U$ for some unitary $U$ and $f_U$ is
the inner automorphism (matrix.innerAut
)
the inner automorphism is unital
the trace of $f_U(x)$ is equal to the trace of $x$
$x$ is Hermitian if and only if $f_U(x)$ is Hermitian
$f_U(x)$ is positive definite if and only if $x$ is positive definite
Schur decomposition, but only for almost Hermitian matrices: given an almost Hermitian matrix $A$, there exists a diagonal matrix $D$ and a unitary matrix $U$ such that $UDU^*=A$
any $^*$-isomorphism on $M_n$ is an inner automorphism
Equations
- f.of_matrix_unitary = (fun (U : โฅ(Matrix.unitaryGroup n ๐)) (x : Matrix.innerAutStarAlg U = f) => U) (Classical.choose โฏ) โฏ
Instances For
Equations
- Matrix.unitaryGroup.conj U = โจ(โU).conj, โฏโฉ
Instances For
Equations
- Matrix.unitaryGroup.kronecker Uโ Uโ = โจMatrix.kroneckerMap (fun (x1 x2 : ๐) => x1 * x2) โUโ โUโ, โฏโฉ