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P. 119

Exponential stability for higher-order impulsive fractional neutral stochastic integro-delay . . .




            E∥(Φy)(ς) − (Φ¯y)(ς)∥ p                                    
  Z ς                    Z ϑ
                                                                       
   T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,  σ 2 (ϑ, τ,
                                     ϑ                         R 2 = E
                                    Z
                    n
             ≤ 3 p−1  E
g(ς, y ς + z ς ,  σ 1 (ϑ, τ, y τ + z τ )dτ)      0                        0

                                                                        y τ + z τ )dτ) − f(ϑ, ¯y ϑ + z ϑ ,
                                    0
                                                                      ϑ
                              ϑ                                     Z
                            Z
                                                 
 p                                          p
               − g(ς, ¯y ς + z ς ,  σ 1 (ϑ, τ, ¯y τ + z τ )dτ)
        σ 2 (ϑ, τ, ¯y τ + z τ )dτ) dϑ∥

                                                                     0
                             0
                                                                         ς                         ϑ
                     ς                         ϑ                       Z                          Z

                    Z                        Z

                       T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,  σ 2 (ϑ, τ, y τ + z τ )dτ)
                   
                                              ≤ E     
T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,  σ 2 (ϑ, τ,
               + E
                                                                        0                         0
                    0                         0
                                                                      y τ + z τ )dτ) − f(ϑ, ¯y ϑ + z ϑ ,
                               ϑ
                              Z

               − f(ϑ, ¯y ϑ + z ϑ ,  σ 2 (ϑ, τ, ¯y τ + z τ )dτ) dϑ∥ p   Z ϑ

                                                                         σ 2 (ϑ, τ, ¯y τ + z τ )dτ) dϑ∥ p
                              0
                     ς
                    Z                                                  0

                       T α (ς − ϑ)[G(ς, ϑ, y ϑ + z ϑ )            ≤ M ς L (1 + M )E∥y ϑ − ¯y ϑ ∥ .
                   
                                                    p  p  p       p            p
               + E
                                                     ς     f       σ 2
                    0
                                        o
               − G(ς, ϑ, ¯y ϑ + z ϑ )]dw(ϑ)∥ p                By using Lemma 4, we have
                      3
                     X
             ≤ 3 p−1    R i .                           (5)
                     i=1                                                  p−1  p  p  p       p  h    p
                                                                      ≤ 2    M ς L (1 + M ) ∥y 0 ∥
                                                                               ς     f       σ 2
            We have to compute the R.H.S of (5). By (H 2 ),               p               p       p
            we get the following.                                       + l  sup E∥y(ϑ)∥ − ∥¯y 0 ∥
                                                                            ϑ∈[0,ς 1 ]
                                                                                           i
                                                                        − l p  sup E∥¯y(ϑ)∥ p
                                  ϑ
                                 Z                                          ϑ∈[0,ς 1 ]

                                                                                     p
            R 1 = E
g(ς, y ς + z ς ,  σ 1 (ϑ, τ, y τ + z τ )dτ)       ≤ 2 p−1 M ς L (1 + M ) l   p
                                                                               p
                                                                                             p
                                                                                  p

                                                                               ς
                                                                                     f
                                                                                             σ 2
                                                                                               p
                                 0                                      × sup E∥y(ϑ) − ¯y(ϑ)∥ .
                                ϑ                                         ϑ∈[0,ς 1 ]
                               Z
                                                     p

                  − g(ς, ¯y ς + z ς ,  σ 1 (ϑ, τ, ¯y τ + z τ )dτ)

                               0                              By Lemma 1, and assumptions (H 1 ), (H 4 ), we
                      h
                ≤ M  g p  E∥y ς + z ς − ¯y ς − z ς ∥ p        get
                        ς
                       Z
                                                               i
                  + E∥   [σ 1 (ϑ, τ, y τ + z τ ) − σ 1 (ϑ, τ, ¯y τ + z τ )]dτ∥ p
                                                                        ς
                                                                       Z
                       0                                              
            h

                      h                             i         R 3 = E
    T α (ς − ϑ) G(ς, ϑ, y ϑ + z ϑ )
                                       p
                                 p
                ≤ M  g p  E∥y ς − ¯y ς ∥ + M E∥y ς − ¯y ς ∥ p
                                       σ 1
                                                                       0
                             p
                                         p
                     p
                ≤ M (1 + M )E∥y ς − ¯y ς ∥ .                       − G(ς, ϑ, ¯y ϑ + z ϑ )dw(ϑ)∥ p  i
                     g
                             σ 1
            By Lemma 4, we have                                             Z ς
                                                                           h
                                                                       p ˜
                                                                 ≤ M C p        E∥G(ς, ϑ, y ϑ + z ϑ )
                                                                      ς
                                 h                                          0
                                      p
                       p
                               p
             ≤ 2 p−1 M (1 + M ) ∥y 0 ∥ + l p  sup E∥y(ϑ)∥ p                            2  i 2
                      g
                              σ 1
                                            ϑ∈[0,ς 1 ]                               p  p   p
                                                                   − G(ς, ϑ, ¯y ϑ + z ϑ )∥  dϑ
                                          i
                      p
               − ∥¯y 0 ∥ − l p  sup E∥¯y(ϑ)∥ p                         p ˜   p  p            p
                           ϑ∈[0,ς 1 ]                            ≤ M C p ς 2 L E∥y ϑ − ¯y ϑ ∥
                                                                                G
                                                                      ς
                                                                                  p
                                                                                     p
                               p
                       p
                                                         p
                                                                           p ˜
                                                                                                              p
             ≤ 2 p−1 M (1 + M ) l  p  sup E∥y(ϑ) − ¯y(ϑ)∥ .      ≤ 2 p−1  M C p ς 2 L l p  sup E∥y(ϑ) − ¯y(ϑ)∥ .
                      g       σ 1                                          ς         G
                                    ϑ∈[0,ς 1 ]                                           ϑ∈[0,ς 1 ]
            By (H 1 ) and (H 3 ), we have the following estima-
            tion:                                             Using these equations in (5), we get
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