Functional Differential Equations
Functional Differential Equations
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DOI:
10.1007/978-94-017-1630-7_4
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发表时间:
1999
期刊:
影响因子:
--
通讯作者:
A. Kim
中科院分区:
文献类型:
--
作者:
A. Kim
42 CHAPTER 4 distinguish the vector 17 x (t) and the function-delay 18 x (t+ s),-T~ s< O. For this reason one can use the following form to present FDE (4.1. 1) x (t)= f (t, x (t), x (t+ s)),-T~ S< 0,(4.1. 5) where under f (""'): R x R n x Q [-T, 0)--+ R n we understand the operator F: R x Q [-T, O]--+ R n acting in the space R x H (remember that spaces Hand Q [-T, O] are isometric). More precisely, the mapping f is the superposition of F and n-1, ie f (t, h)= F [t, n-1 (h)],(t, h) ERxH (here n-1 is the inverse mapping to isometry n: Q [-T, 0]--+ H). In order to find solutions of system (4.1. 5) it is necessary at every moment t to know the vector x (t) and the function-prehistory x (t+ s),-T~ S< O. For this reason a phase space of system (4.1. 5) should be not finite dimensional space R n, but some functional space (space of functions). In this book we consider FDE in the phase space H= R n x Q [-T, 0). The space H= R n x Q [-T, O) is very convenient for distinguishing finite dimensional and infinite dimensional components in the structure FDE. Note, linear FDE are often considered in the Hilbert space R n x£ 2 [-T, 0) that is also the Cartesian product of the finite dimensional space R n and