A Fixed Point for which the Stability Matrix has equal Positive Eigenvalues.
See also Elliptic Fixed Point (Differential Equations), Fixed Point, Hyperbolic Fixed Point (Differential Equations), Stable Improper Node, Stable Node, Stable Spiral Point, 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, 1989.