IndefiniteMatrixQ

IndefiniteMatrixQ[m] gives True if m is explicitly indefinite (has both positive and negative eigenvalues), and False otherwise.

Examples

Test for indefinite matrix:

IndefiniteMatrixQ[{{1, 0}, {0, -1}}]
(* True *)

Definite matrix:

IndefiniteMatrixQ[{{1, 0}, {0, 1}}]
(* False *)

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