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Page 6 of 15                    Sun et al. Complex Eng Syst 2022;2:17  I http://dx.doi.org/10.20517/ces.2022.48


                                                                                                         
               where       (  ) =       (   −       ). Under the LLC, system (14) has a unique maximal global solution on [−  ,    ),
                                                                                                       ∞
                                      
               denoted as       (  ), where    is the explosion time. Then, we prove        = ∞ a.s. Thus, it is necessary to define
                                    ∞                                   ∞
               the stopping time sequence. Let    0 be a constant sufficiently large to satisfy    0 > |      (0)|. For any integer
                  ≥    0, we define the stopping time sequence as follows:
                                                                
                                                   ,   = inf{   ∈ [0,    ), |      (  )| ⩾   }.
                                                              ∞
               Clearly ,      ,   increases as    → ∞ and therefore we set    ∞,   := lim      ,  . Observe that    ∞,   ≤    ∞,   a.s. Thus,
                                                                      →∞
                  ∞,   = ∞, a.s., which yields    ∞,   = ∞ a.s. From the It ˆ formula and condition (9), it is easily proven that
                                                             
                                    (  ∧     ,   ) Λ(   ∧      ,   ,       (   ∧      ,   ),   )
                                                  ∫
                                                       ∧     ,  
                                                              
                             =            0 Λ(   0 ,       (   0 ),   ) +        [  Λ(  ,       (  ),   ) + LΛ(  ,       (  ),   )]    
                                                      0
                                                  ∫
                                                       ∧     ,  
                                                              
                                                                       
                             ≤            0 Λ(   0 ,       (   0 ),   ) +        [     2 |      (  )| −    1   (      (  )) +    2   (      (  ))
                                                       0
                                                    
                                          
                               −    3 |      (  )| +    4 |      (  )| ]    .
               By Lemma 1, we have
                                    ∫
                                        ∧     ,  
                                               
                                               (      (   −       ))    
                                        0
                                           ∫
                                               ∧     ,  
                                                      
                                  ≤          ¯            (      (  ))    
                                               0 −  
                                           ∫                        ∫
                                                0                       ∧     ,  
                                                     
                                                                                
                                  ≤          ¯            (      (  ))     +          ¯            (      (  ))    ,  (15)
                                               0 −                      0
               and
                                     ∫
                                         ∧     ,  
                                                         
                                                 
                                               |      (   −       )|     
                                         0
                                            ∫
                                                 ∧     ,  
                                                        
                                                             
                                    ≤          ¯          |      (  )|     
                                                0 −  
                                            ∫                       ∫
                                                  0                     ∧     ,  
                                                                                    
                                                      
                                                           
                                                                                
                                    ≤          ¯          |      (  )|      +          ¯          |      (  )|     .  (16)
                                                0 −                     0
               Hence,
                            (  ∧     ,   ) Λ(   ∧      ,   ,       (   ∧      ,   ),   )
                                               ∫                                 ∫
                                                   ∧     ,                           ∧     ,  
                                                               
                                                           
                                                                                            
                      ≤    − (   3 −    4 ¯           −      2 )       |      (  )|      − (   1 −    2 ¯          )         (      (  ))    ,
                                                   0                                 0
               where
                                     (                 )          (       ∫             )
                                                                               0
                                   =    sup         0 Λ(   0 ,   ,   ) +    2 ¯              sup       (  )    
                                                                                     0
                                      [   0 −  ,   0 ]              [   0 −  ,   0 ]     0 −  
                                             (       ∫            )
                                                          0
                                                                 
                                    +    4 ¯               sup           0  |  |     
                                               [   0 −  ,   0 ]     0 −  
               is a finite constant. Applying (10) and (11) from Assumption 3, we can deduce that
                                                    (  ∧     ,   ) Λ(   ∧      ,   ,       (   ∧      ,   ),   ) ≤   .
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