IMA Journal of Mathematical Control and Information Advance Access originally published online on June 8, 2006
IMA Journal of Mathematical Control and Information 2007 24(1):115-136; doi:10.1093/imamci/dnl012
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On approximation theorems for controllability of non-linear parabolic problems
Industrial Mathematics Group, Department of Mathematics, Indian Institute of Technology, Bombay, Powai, Mumbai-400076, India
** Email: anil{at}math.iitb.ac.in
*** Email: mcj{at}math.iitb.ac.in
**** Email: akp{at}math.iitb.ac.in
| Abstract |
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In this paper, we consider the following control system governed by the non-linear parabolic differential equation of the form:
[graphic: see PDF]
where A is a linear operator with dense domain and f(t, y) is a non-linear function. We have proved that under Lipschitz continuity assumption on the non-linear function f(t, y), the set of admissible controls is non-empty. The optimal pair (u*, y*) is then obtained as the limit of the optimal pair sequence {(un*, yn*)}, where un* is a minimizer of the unconstrained problem involving a penalty function arising from the controllability constraint and yn* is the solution of the parabolic non-linear system defined above. Subsequently, we give approximation theorems which guarantee the convergence of the numerical schemes to optimal pair sequence. We also present numerical experiment which shows the applicability of our result.
Keywords: controllability; optimal control; non-linear parabolic system; penalty function; Nemytskii operator; C0-semigroup; Lipschitz continuity; generalized Hammerstein equation..
Received on 28 June 2005. accepted on 20 April 2006.