© 2000 by London Mathematical Society
© The London Mathematical Society
Necessary and Sufficient Conditions for Exponential Stability and Ultimate Boundedness of Systems Governed by Stochastic Partial Differential Equations
Department of Mathematics, University of Wales Swansea Singleton Park, Swansea SA2 8PP, k.liu{at}swansea.ac.uk
Received 4 March 1999. Revision received 29 April 1999.
Consider the following infinite dimensional stochastic evolution equation over some Hilbert space H with norm |·|:
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It is proved that under certain mild assumptions, the strong solution Xt(x0)
V
H
V*, t
0, is mean square exponentially stable if and only if there exists a Lyapunov functional
(·, ·):HxR+
R1 which satisfies the following conditions:
(i)c1|x|2k1eµ1t
(x,t)
c2|x|2+k2+k2eµ2t;
(ii) L
(x,t)
c3
(x,t)+k3eµ3t,
x
V, t
0;
where L is the infinitesimal generator of the Markov process Xt and ci, ki, µi, i = 1, 2, 3, are positive constants. As a by-product, the characterization of exponential ultimate boundedness of the strong solution is established as the null decay rates (that is, µi = 0) are considered.
