Article contents
A Remark on a Theorem of Lyapunov
Published online by Cambridge University Press: 20 November 2018
Extract
Consider the linear ordinary differential equation
1
where x ∊ En, the n-dimensional Euclidean space and A is an n × n constant matrix. Using a matrix result of Sylvester and a stability result of Perron, Lyapunov [4] established the following theorem which is basic in the stability theory of ordinary differential equations:
Theorem (Lyapunov). The following three statements are equivalent:
(I) The spectrum σ(A) of A lies in the negative half plane.
(II) Equation (1) is exponentially stable, i.e. there exist μ, K>0 such that every solution x(t) of (1) satisfies
2
where ∥ ∥ denotes the Euclidean norm.
(III) There exists a positive definite symmetric matrix Q, i.e. Q=Q* and there exist q1,q2>0 such that
3
satisfying
4
where I is the identity matrix.
- Type
- Research Article
- Information
- Copyright
- Copyright © Canadian Mathematical Society 1970
References
- 3
- Cited by