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Controllability of Single-valued Chapter | 7  211


                                       d  ð  t
                                 xðtÞ 5   Sðt 2 sÞhðsÞds; ’tAJ;
                                      dt  0
                                              γ
              (ii) if fSðtÞg t $ 0  is analytic and hAC ðJ; HÞ for some γAð0; 1Þ, then the
                 function defined by
                                        ð t
                    xðtÞ 5 SðtÞðhðtÞ 2 hð0ÞÞ 1  S ðt 2 sÞ½hðsÞ 2 hðtފds 1 SðtÞhð0Þ; tAJ
                                           0
                                         0
                 is a mild solution of (7.17) on J;
             (iii) if fSðtÞg t $ 0  is differentiable and hACðJ; ½DðAÞŠÞ then the function
                 x:J-H defined by

                                   ð t
                              xðtÞ 5  S ðt 2 sÞhðsÞds 1 hðtÞ; tAJ
                                      0
                                    0
             is a mild solution of (7.17).

             Lemma 7.6: Let H be a Banach space, G is a closed, convex subset of H, U ^
                                                     ^
                                     ^
             an open subset of G and 0AU. Suppose that F:U-G is a continuous, com-
                        ^
             pact (i.e., FðUÞ is a relatively compact subset of G) map, then either
                                    ^
              (i) F has a fixed point in U; or
                             ^
             (ii) there is a yA@U and λAð0; 1Þ with y 5 λFðyÞ.
                The following hypotheses are considered to prove the main results

                (H 14 ) SðtÞ is compact for all t . 0.
                (H 15 ) f:J 3 C h -H satisfies the following
                (i) fðt; UÞ:C h -H  is  continuous  for  each  tAJ  and  for  each
                    xAC h ; fðU; xÞ:J-H is strongly measurable.
                                                        1
                (ii) There is a positive integrable function nAL ð½0;bŠÞ and a continuous
                    nondecreasing function Λ f : ½0;NÞ-ð0;NÞ such that for every
                    ðt; xÞAJ 3 C h ,

                                 2
                                             2
                          Ejfðt; xÞj # nðtÞΛ f ðOxO Þ;  lim inf  Λ f ðrÞ  5 ϒ 1 , N:
                                 H           C h  r-N    r
                                                    2
                                                           2
               (iii) For arbitrary ξ ; ξ AC h ; satisfying Oξ O ; Oξ O # ρ, there exists a
                                1  2              1 C h  2 C h
                    M f ðρÞ . 0 such that
                                              2             2
                             E fðt; ξ Þ2fðt; ξ Þ # M f ðρÞ:ξ 2ξ : :


                                   1      2           1   2 C h
                (H 16 ) The function σ:J 3 C h -LðK; HÞ satisfies the following
                (i) For each tAJ;  σðt; UÞ:C h -LðK; HÞ is continuous and for each
                    xAC h ; σðU; xÞ:J-LðK; HÞ is strongly measurable.
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