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ON THE STRUCTURE OF THE SOLUTION SET OF A FUNCTIONAL DIFFERENTIAL SYSTEM
ON AN UNBOUNDED INTERVAL

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*Zbynek Kubacek*

**Address.** Department of Mathematical Analysis, Faculty of Mathematics
and Physics
Comenius University, Mlynsk\'a dolina, 842 15 Bratislava, Slovak Republic

**E-mail:** kubacek@fmph.uniba.sk

**Abstract.** It is proved that under some conditions the set of
all solutions of an initial value problem for $n$-th order functional differential
system on an unbounded interval is a compact $R_\delta$.

**AMSclassification.** 34K05, 34K25

**Keywords.** initial value problem, functional differential system,
$R_\delta-set$