Hoffman–Wielandt inequality

Target entity: Hoffman–Wielandt inequality
Context triple: [Alan Hoffman, notableConcept, Hoffman–Wielandt inequality]

• A. Weyl inequalities
  Weyl inequalities are fundamental results in linear algebra that bound the eigenvalues of sums of Hermitian (or symmetric) matrices in terms of the eigenvalues of the individual matrices.
• B. Hadamard inequality
  The Hadamard inequality is a fundamental result in linear algebra and analysis that bounds the absolute value of a determinant by the product of the Euclidean norms of its row or column vectors.
• C. Courant–Fischer min–max theorem
  The Courant–Fischer min–max theorem is a fundamental result in linear algebra and spectral theory that characterizes the eigenvalues of a Hermitian (or symmetric) matrix via variational min–max principles over subspaces.
• D. Friedrichs inequality
  Friedrichs inequality is a fundamental result in functional analysis and partial differential equations that provides bounds on the norms of functions in terms of their derivatives, playing a key role in the theory of Sobolev spaces and boundary value problems.
• E. Schur product theorem
  The Schur product theorem is a result in linear algebra stating that the entrywise (Hadamard) product of two positive semidefinite matrices is itself positive semidefinite.
• F. None of above. chosen
• G. Unsure - the case is ambiguous/there is not enough information to decide.

Target entity: Hoffman–Wielandt inequality
Target entity description: The Hoffman–Wielandt inequality is a fundamental result in matrix analysis that bounds the difference between the eigenvalues of two normal matrices in terms of the Frobenius norm of their difference.

• A. Weyl inequalities
  Weyl inequalities are fundamental results in linear algebra that bound the eigenvalues of sums of Hermitian (or symmetric) matrices in terms of the eigenvalues of the individual matrices.
• B. Hadamard inequality
  The Hadamard inequality is a fundamental result in linear algebra and analysis that bounds the absolute value of a determinant by the product of the Euclidean norms of its row or column vectors.
• C. Courant–Fischer min–max theorem
  The Courant–Fischer min–max theorem is a fundamental result in linear algebra and spectral theory that characterizes the eigenvalues of a Hermitian (or symmetric) matrix via variational min–max principles over subspaces.
• D. Friedrichs inequality
  Friedrichs inequality is a fundamental result in functional analysis and partial differential equations that provides bounds on the norms of functions in terms of their derivatives, playing a key role in the theory of Sobolev spaces and boundary value problems.
• E. Schur product theorem
  The Schur product theorem is a result in linear algebra stating that the entrywise (Hadamard) product of two positive semidefinite matrices is itself positive semidefinite.
• F. None of above. chosen