A fixed point for which the stability matrix has one zero eigenvector with positive eigenvalue 
.
Unstable Star
See also
Elliptic Fixed Point, Fixed Point, Hyperbolic Fixed Point, Stable Improper Node, Stable Node, Stable Spiral Point, Stable Star, Unstable Improper Node, Unstable Node, Unstable Spiral PointExplore with Wolfram|Alpha
References
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.Referenced on Wolfram|Alpha
Unstable StarCite this as:
Weisstein, Eric W. "Unstable Star." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/UnstableStar.html