Park, Jong Yeoul; Kang, Sang Nam Approximate controllability of neutral functional differential system with unbounded delay. (English) Zbl 0995.93009 Int. J. Math. Math. Sci. 26, No. 12, 737-744 (2001). The authors study the approximate controllability of neutral functional differential systems with unbounded delay of the form \[ {d\over dt}\{x(t)+F(t,x_t)\}=Ax(t)+G(t,x_t)+Bv(t), 0<t<T, x_0=\phi, \] where \(F,G: [0,T]\times {\mathcal B}\to X\) are continuous functions, \({\mathcal B}\) is an abstract phase space, \(A\) is the infinitesimal generator of an analytic semigroup of bounded linear operators on a Banach space \(X,\) the control function \(v(\cdot)\) is given in \(L^2(0,T:V),\) which is a Banach space of admissible control functions, with \(V\) as a Banach space. Finally, \(B\) is a bounded linear operator from \(L^2(0,T:V)\) into \(L^2(0,T:X).\) An example which illustrates the theoretical results is also presented. Reviewer: S.K.Ntouyas (Ioannina) Cited in 12 Documents MSC: 93B05 Controllability 93C23 Control/observation systems governed by functional-differential equations 93C25 Control/observation systems in abstract spaces 34K40 Neutral functional-differential equations Keywords:controllability; neutral functional differential system; unbounded delay PDFBibTeX XMLCite \textit{J. Y. Park} and \textit{S. N. Kang}, Int. J. Math. Math. Sci. 26, No. 12, 737--744 (2001; Zbl 0995.93009) Full Text: DOI EuDML Link