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1. Hessian Matrix

   Linked via "indefinite"

   Local Minimum: If $\mathbf{H}(\mathbf{c})$ is positive definite (all eigenvalues $\lambda_i > 0$), the function curves upward in all directions, indicating a local minimum. This is the sought-after configuration for stable chemical products [2].
   Local Maximum: If $\mathbf{H}(\mathbf{c})$ is negative definite (all eigenvalues $\lambda_i < 0$), the function curves downward in all directions, indicating a [l…