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CPS1458 KHOO W.C et al.
                      (iii)   the  conditional  distribution  on   ( ∘ +1   , … ,  ∘ +   | =
                                                                           
                                                                                       
                                                                
                                                                                          
                              ,  −1 ) is equal to ( ∘ +1   , … ,  ∘ +   | =  ), where  −1
                              
                                                                       
                                                           
                                                                          
                                                                               
                             abbreviates the process history of all   and  ∘ +    for  ≤  − 1
                                                                               
                                                                  
                             and  = 1, … , .
                      The MPT(p) process has been shown to be stationary and due to space
                  constrain will be omitted. For model fitting in this paper the Poisson marginal
                  distribution is considered. Let   be Poisson process with mean , which fulfils
                                                
                  the Definition of Equation (5), the conditional pgf of   with Poisson marginal
                                                                      
                  is given by

                                                                         
                                  () = ∑  (1 −  + )   −  +  (−1)  − ∑   (−1)
                          | −1 ,…, −                           
                                         =1                              =1

                                                                         1      (1−)
                  To ensure model validity, the parameters must fulfill    >       for  =
                                                                       ∑ =1   
                                      
                                 (1− ∑    ) 
                  1, …, with  =     =1   .
                                      
                             
                                   1−∑ =1   

                      Next, we show the statistical and regression properties of the model. The
                  conditional moments of Poisson MPT(p) process is defined as follows. Let 
                                                                                            
                  be  a  MPT(p)  process  with  Poisson  marginal  distribution.  The  conditional
                  moments are given by

                   (a) ( | −1 , … ,  − ) =  ∑      + (1 − ∑    )
                          
                                                                         
                                                                      
                                                    −
                                               =1
                                                                 =1
                   (b) ( | −1 , … ,  − )
                            
                                                                 
                                            2
                                                                              2
                                                                                   2
                         =  ∑    + ∑     ( −  − 1) + (1 − ∑  ) ( +  )
                                                                                   
                                 −
                                               −
                                                                         
                                                                              
                           =1        =1                         =1
                                                              2
                                             2
                                      2
                                   −  ∑   − 2  − (1 − ∑  )   2
                                            
                                                                
                                        =1               =1
                                                      
                                   − 2 ∑   − (1 − ∑  ) 
                                                                
                                                            
                                             
                                        =1           =1

                  The  autocorrelation  structure  of  Poisson  MPT(p)  process  given  next.  Let
                  () = ( ,  − ) denote the autocovariance function. It is given by
                               

                                                  
                                       () =  ∙ ∑  ∙ (| − |)
                                                      
                                                 =1

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