Chetaev instability theorem
The Chetaev instability theorem for dynamical systems states that if there exists, for the system [math]\displaystyle{ \dot{\textbf{x}} = X(\textbf{x}) }[/math] with an equilibrium point at the origin, a continuously differentiable function V(x) such that
- the origin is a boundary point of the set [math]\displaystyle{ G = \{\mathbf{x} \mid V(\mathbf{x})\gt 0\} }[/math];
- there exists a neighborhood [math]\displaystyle{ U }[/math] of the origin such that [math]\displaystyle{ \dot{V}(\textbf{x})\gt 0 }[/math] for all [math]\displaystyle{ \mathbf{x} \in G \cap U }[/math]
then the origin is an unstable equilibrium point of the system.
This theorem is somewhat less restrictive than the Lyapunov instability theorems, since a complete sphere (circle) around the origin for which [math]\displaystyle{ V }[/math] and [math]\displaystyle{ \dot{V} }[/math] both are of the same sign does not have to be produced.
It is named after Nicolai Gurevich Chetaev.
Applications
Chetaev instability theorem has been used to analyze the unfolding dynamics of proteins under the effect of optical tweezers.[1]
See also
- Lyapunov function — a function whose existence guarantees stability
References
- ↑ Mohammadi, A.; Spong, Mark W. (2022). "Chetaev Instability Framework for Kinetostatic Compliance-Based Protein Unfolding". IEEE Control Systems Letters 6: 2755–2760. doi:10.1109/LCSYS.2022.3176433. ISSN 2475-1456. https://ieeexplore.ieee.org/document/9778188.
- Hazewinkel, Michiel, ed. (2001), "Chetaev theorems", Encyclopedia of Mathematics, Springer Science+Business Media B.V. / Kluwer Academic Publishers, ISBN 978-1-55608-010-4, https://www.encyclopediaofmath.org/index.php?title=Chetaev_theorems&oldid=12645
Further reading
- Shnol, Emmanuil (2007). "Chetaev function". Scholarpedia 2 (9): 4672. doi:10.4249/scholarpedia.4672. Bibcode: 2007SchpJ...2.4672S.
Original source: https://en.wikipedia.org/wiki/Chetaev instability theorem.
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