A Fixed Point for which the Stability Matrix has Eigenvalues , also called a Saddle Point.
See also Elliptic Fixed Point (Differential Equations), Fixed Point, Stable Improper Node, Stable Spiral Point, Stable Star, Unstable Improper Node, Unstable Node, Unstable Spiral Point, Unstable Star
Tabor, M. ``Classification of Fixed Points.'' §1.4.b in
Chaos and Integrability in Nonlinear Dynamics: An Introduction. New York: Wiley, pp. 22-25,