The Chetaev instability theorem for
dynamical system
In mathematics, a dynamical system is a system in which a function describes the time dependence of a point in an ambient space. Examples include the mathematical models that describe the swinging of a clock pendulum, the flow of water i ...
s states that if there exists, for the system
with an
equilibrium point
In mathematics, specifically in differential equations, an equilibrium point is a constant solution to a differential equation.
Formal definition
The point \tilde\in \mathbb^n is an equilibrium point for the differential equation
:\frac = \m ...
at the origin, a continuously differentiable function V(x) such that
# the origin is a
boundary point of the set
;
# there exists a
neighborhood of the origin such that
for all
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
and
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.
See also
*
Lyapunov function
In the theory of ordinary differential equations (ODEs), Lyapunov functions, named after Aleksandr Lyapunov, are scalar functions that may be used to prove the stability of an equilibrium of an ODE. Lyapunov functions (also called Lyapunov’s se ...
— a function whose existence guarantees stability
References
*
Further reading
*{{cite journal , doi=10.4249/scholarpedia.4672, doi-access=free , title=Chetaev function , year=2007 , last1=Shnol , first1=Emmanuil , journal=
Scholarpedia
''Scholarpedia'' is an English-language wiki-based online encyclopedia with features commonly associated with open-access online academic journals, which aims to have quality content in science and medicine.
''Scholarpedia'' articles are written ...
, volume=2 , issue=9 , page=4672 , bibcode=2007SchpJ...2.4672S
Theorems in dynamical systems
Stability theory