IndefiniteMatrixQ

IndefiniteMatrixQ[m]

gives True if m is explicitly indefinite, and False otherwise.

Details and Options

  • A matrix m is indefinite if its Hermitian part is neither a positive nor a negative semidefinite matrix.
  • IndefiniteMatrixQ works for symbolic as well as numerical matrices.
  • For approximate matrices, the option Tolerance->t can be used to indicate that all eigenvalues λ satisfying λt λmax are taken to be zero where λmax is an eigenvalue largest in magnitude.
  • The option Tolerance has Automatic as its default value.

Examples

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Basic Examples  (1)

Test if a matrix is explicitly indefinite:

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The quadratic form has positive and negative values for different vectors :

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Scope  (6)

Options  (1)

Applications  (2)

Properties & Relations  (6)

Possible Issues  (1)

See Also

PositiveDefiniteMatrixQ  NegativeDefiniteMatrixQ  PositiveSemidefiniteMatrixQ  NegativeSemidefiniteMatrixQ  HermitianMatrixQ  SymmetricMatrixQ  Eigenvalues  SquareMatrixQ

Introduced in 2014
(10.0)