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Project-declaredLean 4.28.0 · mathlib@8f9d9cff6bd7

Intermediate ineq

intermediate_ineq

Plain-language statement

The intermediate operator inequality: ρ_AB ⊗ σ_C⁻¹ ≤ (ρ_A ⊗ σ_BC⁻¹).reindex(assoc⁻¹). This is derived from W_mat_sq_le_one by algebraic manipulation (conjugation and simplification).

Exact Lean statement

theorem intermediate_ineq [Nonempty dA] [Nonempty dB] [Nonempty dC]
    (ρAB : HermitianMat (dA × dB) ℂ) (σBC : HermitianMat (dB × dC) ℂ)
    (hρ : ρAB.mat.PosDef) (hσ : σBC.mat.PosDef) :
    ρAB ⊗ₖ (σBC.traceLeft)⁻¹ ≤
      (ρAB.traceRight ⊗ₖ σBC⁻¹).reindex (Equiv.prodAssoc dA dB dC).symm

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem intermediate_ineq [Nonempty dA] [Nonempty dB] [Nonempty dC]    (ρAB : HermitianMat (dA × dB) ℂ) (σBC : HermitianMat (dB × dC) ℂ)    (hρ : ρAB.mat.PosDef) (hσ : σBC.mat.PosDef) :    ρAB ⊗ₖ (σBC.traceLeft)⁻¹       (ρAB.traceRight ⊗ₖ σBC⁻¹).reindex (Equiv.prodAssoc dA dB dC).symm := by  have h_sorted : (ρAB.traceRight⁻¹.sqrt.mat ⊗ₖ σBC.sqrt.mat).reindex (Equiv.prodAssoc dA dB dC).symm (Equiv.prodAssoc dA dB dC).symm * (ρAB ⊗ₖ (σBC.traceLeft)⁻¹).mat * (ρAB.traceRight⁻¹.sqrt.mat ⊗ₖ σBC.sqrt.mat).reindex (Equiv.prodAssoc dA dB dC).symm (Equiv.prodAssoc dA dB dC).symm  (1 : Matrix ((dA × dB) × dC) ((dA × dB) × dC) ℂ) := by    convert W_mat_sq_le_one ρAB σBC hρ hσ using 1;    convert W_mat_sq_eq_conj ρAB σBC hρ hσ |> Eq.symm using 1;  convert h_sorted using 1;  rw [HermitianMat.le_iff];  rw [  S_mat_conj_rhs_eq_one ρAB σBC hρ hσ ];  simp only [ Matrix.posSemidef_iff_dotProduct_mulVec ]  constructor <;> intro h <;> simp_all  · convert h_sorted using 1;    convert S_mat_conj_rhs_eq_one ρAB σBC hρ hσ using 1;  · have := S_mat_isUnit ρAB σBC hρ hσ;    cases' this.nonempty_invertible with u hu;    have h_pos_semidef : Matrix.PosSemidef ((S_mat ρAB σBC)⁻¹ * (S_mat ρAB σBC * ((ρAB.traceRight ⊗ₖ σBC⁻¹).reindex (Equiv.prodAssoc dA dB dC).symm).mat * S_mat ρAB σBC - S_mat ρAB σBC * (ρAB ⊗ₖ (σBC.traceLeft)⁻¹).mat * S_mat ρAB σBC) * (S_mat ρAB σBC)⁻¹ᴴ) := by      exact Matrix.PosSemidef.mul_mul_conjTranspose_same h (S_mat ρAB σBC)⁻¹;    simp_all [ Matrix.mul_assoc, Matrix.sub_mul, Matrix.mul_sub ];    simp_all [ Matrix.posSemidef_iff_dotProduct_mulVec, Matrix.IsHermitian ];    have h_conj : (S_mat ρAB σBC)ᴴ = S_mat ρAB σBC := by      unfold S_mat; simp [ Matrix.conjTranspose_kronecker, Matrix.conjTranspose_submatrix ] ;    simp_all [  Matrix.conjTranspose_nonsing_inv ]
Project
quantumInfo
License
MIT
Commit
56e83a9288a3
Source
QuantumInfo/Finite/Entropy/SSA.lean:761-784

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