- 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 λ≤t λmax are taken to be zero where λmax is an eigenvalue largest in magnitude.
- The option Tolerance has Automatic as its default value.
Introduced in 2014