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Estimation of time dependent parameters in general parabolic evolution systems. (English) Zbl 0869.35047
The authors present a unified theoretical and computational approach for estimating time dependent parameters in abstract parabolic systems. Results are proved initially, within the framework of a Gelfand triple $$V\hookrightarrow H\hookrightarrow V^*$$, for the abstract non-autonomous equation $\dot u(t,q)= A(t,q)u(t,q)+ F(t,u(t,q),q),\quad u(0,q)= u_0(q).\tag{1}$ In (1) it is assumed that the parameter $$q$$ belongs to a compact separable metric space, the linear operator $$A(t,q)$$ is determined by a (suitably restricted) time and parameter dependent sesquilinear form on $$V$$, and the nonlinear term $$F$$ satisfies certain continuity conditions. The existence and uniqueness of a solution to a weak formulation of (1) is established and a convergence theory for least squares based parameter estimation is produced. The general theory is then applied to the specific cases of a contaminated groundwater model and the Euler-Bernoulli beam equation.
Reviewer: W.Lamb (Glasgow)

##### MSC:
 35G10 Initial value problems for linear higher-order PDEs 35K25 Higher-order parabolic equations 34G20 Nonlinear differential equations in abstract spaces 35B30 Dependence of solutions to PDEs on initial and/or boundary data and/or on parameters of PDEs 41A65 Abstract approximation theory (approximation in normed linear spaces and other abstract spaces)
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