Definition of saddle point in English:
saddle point
noun
Mathematics1A point at which a curved surface is locally level but at which its curvature in two directions differs in sign, i.e. for a surface defined by a function f of x and y, a point at which ∂ f /∂ x = ∂ f /∂ y = 0 and (∂2 f /∂ x 2)(∂2 f /∂ y 2) < 0.
2(In a zero-sum game) the joint outcome of the two parties following their unmixed optimal strategies, where these exist.
Origin
Early 20th century; earliest use found in American Journal of Mathematics.
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