Linear functionals #
This file contains results for linear functionals on the set of $n \times n$ matrices $M_n$ over $\mathbb{C}$.
Main results #
module.dual.apply
module.dual.is_pos_map_iff
module.dual.is_faithful_pos_map_iff
module.dual.is_tracial_faithful_pos_map_iff
module.dual.is_faithful_pos_map_iff_is_inner
the matrix of a linear map φ : M_n →ₗ[R] R
is given by
∑ i j, stdBasisMatrix j i (φ (stdBasisMatrix i j 1))
.
Equations
- φ.matrix = ∑ i : n, ∑ j : n, Matrix.stdBasisMatrix j i (φ (Matrix.stdBasisMatrix i j 1))
Instances For
given any linear functional φ : M_n →ₗ[R] R
, we get φ a = (φ.matrix ⬝ a).trace
.
we linear maps φ_i : M_[n_i] →ₗ[R] R
, we define its direct sum as the linear map (Π i, M_[n_i]) →ₗ[R] R
.
Equations
- Module.Dual.pi φ = { toFun := fun (a : PiMat R k s) => ∑ i : k, (φ i) (a i), map_add' := ⋯, map_smul' := ⋯ }
Instances For
Equations
- φ.pi_of x = φ ∘ₗ Matrix.includeBlock
Instances For
for direct sums, we get φ x = ∑ i, ((φ i).matrix ⬝ x i).trace
Any linear functional $f$ on $M_n$ is given by a unique matrix $Q \in M_n$ such that $f(x)=\operatorname{Tr}(Qx)$ for any $x \in M_n$.
Equations
- Module.Dual.pi' φ = Module.Dual.pi φ ∘ₗ Matrix.isBlockDiagonalPiAlgEquiv.toLinearMap
Instances For
⨁_i φ_i ι_i (x_i) = φ_i (x_i)
A linear functional $φ$ on $M_n$ is positive if $0 ≤ φ (x^*x)$ for all $x \in M_n$.
Instances For
A linear functional $φ$ on $M_n$ is unital if $φ(1) = 1$.
Instances For
A linear functional is called a state if it is positive and unital
- toIsPosMap : φ.IsPosMap
- toIsUnital : φ.IsUnital
Instances
A linear functional $f$ on $M_n$ is said to be faithful if $f(x^*x)=0$ if and only if $x=0$ for any $x \in M_n$.
Instances For
A linear functional $f$ is positive if and only if there exists a unique positive semi-definite matrix $Q\in M_n$ such $f(x)=\operatorname{Tr}(Qx)$ for all $x\in M_n$.
A linear functional $f$ is a state if and only if there exists a unique positive semi-definite matrix $Q\in M_n$ such that its trace equals $1$ and $f(x)=\operatorname{Tr}(Qx)$ for all $x\in M_n$.
A positive linear functional $f$ is faithful if and only if there exists a positive definite matrix such that $f(x)=\operatorname{Tr}(Qx)$ for all $x\in M_n$.
- toIsPosMap : φ.IsPosMap
- toIsFaithful : φ.IsFaithful
Instances
A linear functional $φ$ is a faithful and positive if and only if there exists a unique positive definite matrix $Q$ such that $φ(x)=\operatorname{Tr}(Qx)$ for all $x\in M_n$.
A state is faithful $f$ if and only if there exists a unique positive definite matrix $Q\in M_n$ with trace equal to $1$ and $f(x)=\operatorname{Tr}(Qx)$ for all $x \in M_n$.
A linear functional $f$ is tracial if and only if $f(xy)=f(yx)$ for all $x,y$.
Instances For
A linear functional is tracial and positive if and only if there exists a non-negative real $α$ such that $f\colon x \mapsto \alpha \operatorname{Tr}(x)$.
A linear functional is tracial and positive if and only if there exists a unique non-negative real $α$ such that $f\colon x \mapsto \alpha \operatorname{Tr}(x)$.
A linear functional $f$ is tracial positive and faithful if and only if there exists a positive real number $\alpha$ such that $f\colon x\mapsto \alpha \operatorname{Tr}(x)$.
A linear functional $f$ on $M_n$ is positive and faithful if and only if $(x,y)\mapsto f(x^*y)$ defines an inner product on $M_n$.
Equations
- φ.NormedAddCommGroup = InnerProductSpace.Core.toNormedAddCommGroup
Instances For
Equations
- One or more equations did not get rendered due to their size.
Instances For
Equations
- Module.Dual.PiNormedAddCommGroup = PiLp.normedAddCommGroup 2 fun (j : k) => Mat ℂ (s j)
Instances For
Equations
- Module.Dual.pi.InnerProductSpace = PiLp.innerProductSpace fun (j : k) => Mat ℂ (s j)