If for a difference equation no stability theorem applies, it is necessary to examine this difference equation directly. For many equations, however, it is neither obvious whether solutions are bounded or stable, nor is it trivial to prove such behavior. A useful way to prove boundedness is to find
Invariants and related Liapunov functions for difference equations
✍ Scribed by M.R.S Kulenović
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 360 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0893-9659
No coin nor oath required. For personal study only.
✦ Synopsis
Consider the difference equation
where xn is in R k and f : D --~ D is continuous where D C R k. Suppose that I : R k ~ R is a continuous invariant, that is, I(f(x)) = I(x) for every x E D. We will show that if I attains an isolated minimum or maximum value at the equilibrium (fixed) point p of this system, then there exists a Liapunov function, namely :t=(l(x) -I(p)) and so the equilibrium p is stable. This result is then applied to some difference equations appearing in different fields of applications.
📜 SIMILAR VOLUMES
In this paper we find invariants for some difference equations and for some systems of difference equations and then we utilize them to see whether all solutions of the equations are bounded and persist.
has presented some invariants for difference equations and systems of difference equations of rational Ž . form with constant and periodic coefficients of certain period . We report that the presented invariants as well as their difference equations can be generalized.