In the context of mathematical optimization and differential geometry, the term "Hessian pair" generally refers to a specific combination of the Hessian matrix and a function that is being analyzed. The Hessian matrix, which represents the second-order partial derivatives of a scalar function, provides important information about the curvature of the function, and thus about the nature of its critical points (e.g., whether they are minima, maxima, or saddle points).
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