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P. 116

D. Kasinathan et.al. / IJOCTA, Vol.15, No.1, pp.103-122 (2025)


            (Φy)(ς)                                                         y τ + z τ )dτ) dϑ∥ p
                
                 0,      ς ∈ J 0                                                ς
                                                                                Z
                
                
                                               ), 0)                                                            p
                 S α (ς)g(0, φ + ˜p(y ς 1  , y ς 2  , . . . , y ς n       + E∥   T α (ς − ϑ)G(ς, ϑ, y ϑ + z ϑ )dw(ϑ)∥
                
                 +T α (ς)[y 1 + η]
                
                
                                 ς                                              0
                
                
                               R
                 −g(ς, y ς + z ς , σ 1 (ς, τ, y τ + z τ )dτ)                    ς
                
                
                                                                               Z                        o
                               0                                                                  H    p
                                                                          + E∥   T α (ς − ϑ)σ(ϑ)dB (ϑ)∥
                      ς
                
                    R                                                                            Q
                 + T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,
                
                
                                                                               0
                    0
                
                
                 ϑ                                                             6
                 R                                                             X
                                                                      p     p−1
                    σ 2 (ϑ, τ, y τ + z τ )dτ) dϑ             E∥Φy(ς)∥ ≤ 6          I i .                 (2)
                
                
                 0
                
                      ς                                                         i=1
                
                    R
                 + T α (ς − ϑ)G(ς, ϑ, y ϑ + z ϑ )dw(ϑ)
                
                
                
                     0
                
                                                             We compute the terms on the R.H.S of (2). From
                     ς
                
                     R                 H
                 + T α (ς − ϑ)σ(ϑ)dB (ϑ),      ς ∈ [0, ς 1 ]  hypothesis (H 1 ), we have the following estima-
                
                
                                      Q
                     0
                
                                                             tion:
                 .
                
                
                 .
                 .
                
                                                ), 0)
                
              =                                                                                         p
                   S α (ς)g(0, φ + ˜p(y ς 1
                                         , . . . , y ς n
                                     , y ς 2
                 +T α (ς)[y 1 + η]                           I 1 = E∥S α (ς)g(0, φ + ˜p(y ς 1  , y ς 2  , . . . , y ς n ), 0)∥
                
                                ς
                                                                          p                               p
                                R                                                                      ), 0)∥
                 −g(ς, y ς + z ς , σ 1 (ς, τ, y τ + z τ )dτ)    ≤ ∥S α (ς)∥ E∥g(0, φ + ˜p(y ς 1  , y ς 2  , . . . , y ς n
                
                
                
                                0                                    p−1             p
                                                                         p
                                                                            ¯           ¯
                     ς                                          ≤ 2    M M g [E∥φ∥ + L p ]
                                                                        ϑ
                     R
                 + T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,                                   p
                
                
                                                             I 2 = E∥T α (ς)[y 1 + η]∥
                     0
                
                
                
                 ϑ                                                 p−1  p       p       p
                
                 R                                              ≤ 2    M [E∥y 1 ∥ + E∥η∥ ].
                                                                          ς
                    σ 2 (ϑ, τ, y τ + z τ )dτ) dϑ
                
                
                 0
                
                     ς
                
                     R
                                                             By using hypothesis (H 2 ), we get the following
                 + T α (ς − ϑ)G(ς, ϑ, y ϑ + z ϑ )dw(ϑ)
                
                
                                                             estimation:
                     0
                
                     ς
                
                     R
                                      H
                 + T α (ς − ϑ)σ(ϑ)dB (ϑ)
                
                                      Q
                
                    0
                      P              1                                              ϑ
                 +        S α (ς − ς k )I (y ς k  + z ς k )                        Z
                
                
                                     k
                     0<ς k <ς                                                                            p
                                                                                     σ 1 (ϑ, τ, y τ + z τ )dτ)∥
                                                               I 3 = E∥g(ς, y ς + z ς ,
                       P
                 +                             ),
                                     2
                
                                      k
                           T α (ς − ς k )I (y ς k  + z ς k
                
                                                                                   0
                    0<ς k <ς
                
                                 ∀ ς ∈ (ς k , ς k+1 ], k = 1, m.   ≤ M (1 + M )E∥y ς + z ς ∥
                                                                      ¯ p       p           p
                                                                        g
                                                                                 σ 1
                                                                                     ∗
                                                                       ¯ p
                                                                                 p
                                                                   ≤ M (1 + M ) b .
                                                                        g
                                                                                 σ 1
            To prove that Φ has a unique fixed point, it is   By (H 1 ), (H 2 )(ii), (H 3 ) and H¨older’s inequality,
            interesting to see that finding the fixed point of
            Φ in H is same as finding the mild solutions of
            (1) in H. Our proof will be divided into two steps.               ς
                                                                            Z

                                                                    I 4 = E∥   T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,
            Step 1: We claim that Φ(B b ) ⊂ B b . If it is not               0
            true, then for each b > 0, ∃ a function y ∈ B b ,              Z ϑ

            but Φ(B b ) ⊈ B b for ς ∈ J.                                     σ 2 (ϑ, τ, y τ + z τ )dτ) dϑ∥ p
            Case (i): For ς ∈ [0, ς 1 ],
                                                                           0
            b ≤ E∥(Φy)(ς)∥ p                                                  ς
                                                                             Z
                    n                                                  ≤ E     ∥T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,
              ≤ 6 p−1  E∥S α (ς)g(0, φ + ˜p(y ς 1  , y ς 2  , . . . , y ς n ), 0)∥ p
                                                                             0
                + E∥T α (ς)[y 1 + η]∥ p                                     ϑ
                                                                           Z
                                                                                                    p
                                 ϑ
                                Z                                            σ 2 (ϑ, τ, y τ + z τ )dτ) dϑ∥
                + E∥g(ς, y ς + z ς ,  σ 1 (ϑ, τ, y τ + z τ )dτ)∥ p
                                                                           0
                                                                                              ∗
                                                                                 p
                                                                                          p
                                                                            p p
                                0                                      ≤ M ς [L (1 + M )] b .
                                                                            ς
                                                                                 f
                                                                                         σ 2
                      ς                        ϑ
                     Z                        Z

                + E∥    T α (ς − ϑ) f(ϑ, y ϑ + z ϑ ,  σ 2 (ϑ, τ,  By Lemma 1, assumptions (H 1 ) and (H 4 ), we es-
                                                              timate
                     0                        0
                                                           110
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