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Controllability of Fractional Chapter | 8  243


                Since y n -y ; it follows from Lemma 8.3 that, for some y AN F;x  ; then
                          q2p      q2p         q2p           q2p
              Ψ ðtÞ2E q2p ðAt  Þx 0 1At  E q2p;q2p11 ðAt  Þx 0 2tE q2p;2 ðAt  Þx 0
                                                                 0
               ð t                                  ð s
                     q21          q2p
             2 ðt2sÞ   E q2p;q ðAðt2sÞ  Þ Bu x;  ðsÞ1v ðsÞ1  Gðθ;x ðθÞÞdwðθÞ ds AΛðN F;x  Þ:
                0                                    0
                Clearly, for each tAJ; one can set
                            q2p      q2p           q2p            q2p
             : Ψ n ðtÞ 2 E q2p ðAt  Þx 0 1 At  E q2p;q2p11 ðAt  Þx 0 2 tE q2p;2 ðAt  Þx 0
                                                                      0
               ð  t                                   ð  s
                      q21           q2p
              2 ðt2sÞ   E q2p;q ðAðt2sÞ  Þ Bu x;n ðsÞ 1 v n ðsÞ 1  Gðθ; x n ðθÞÞdwðθÞ ds
                                                        0
                0
              2 Ψ ðtÞ 2 E q2p ðAt  q2p Þx 0 1 At q2p E q2p;q2p11 ðAt q2p Þx 0 2 tE q2p;2 ðAt q2p Þx 0 0
                t                                     s
               ð                                     ð
                     q21           q2p                                   2
             2 ðt2sÞ    E q2p;q ðAðt2sÞ  Þ Bu x; ðsÞ1v ðsÞ1 Gðθ; x ðθÞÞdwðθÞ ds : -0

                                                                        B
                0                                     0
             as n-N: From Lemma 8.2, it can be concluded that Φ is u.s.c. As a conse-
             quence of Lemma 8.4, it is clear that Φ has a fixed point which is the solu-
             tion of the system (8.1).  &
             Theorem 8.3: (Nonconvex Case) Assume that conditions (H4) (H5) are sat-
             isfied, then the system (8.1) has at least one solution on J; provided that
                                          2q
                                        T   2    2    2
                             4mðtÞC 2 1 1  n :B: :B : l , 1:            ð8:5Þ
                                            4
                                         q 2
             Proof: Under the assumption (H5) it is easy to see that for each xAB; the set
             S F;x is nonempty. Therefore, F has a nonempty measurable selection (by
             Theorem 8.1). First show that Φ defined in Theorem 8.2 satisfies the assump-
             tion of Lemma 8.5. The proof will be given in two steps.
                Step 1. ΦðxÞAP cl ðBÞ for each xAB:
                Indeed, let ðΨ n Þn $ 0AΦðxÞ such that Ψ n -Ψ: Then, ΨAB and there exists
             v n AN F;x such that, for each tAJ; Ψ n ðtÞ is defined in (8.4). Using (H5), one
             can have
                                                   2
                                jv n ðtÞj # mðtÞ 1 mðtÞ:x: ; nAℕ
             for a.e. tAJ:
                The Lebesgue dominated convergence theorem implies that
                                  :v n 2 v: 2 -0as n-N:
                                         L
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