Page 118 - Special Topic Session (STS) - Volume 3
P. 118

STS518 B.H. Jasiulis G. et al.
                   є   a counterpart of a classical characteristic function called generalized
                       +
                  characteristic function


                  Each generalized convolution is uniquely determined by the probability kernel
                    ⋄  , i.e.
                        
                   

                  for every  ,   .
                               2
                            1
                                   +

                     Example 1. The -convolution,   >  0,  is defined, for , ,   ≥  0, by   ⋄
                                                                                          
                                         
                                               
                        =   ,  where    =  +     and  with  homomorphism  ℎ( ) =
                                                                                        
                      
                      {− }.
                             

                     Example 2. The Kendall convolution Δα is defined in the following way:

                     for  0  ≤    ≤  1  and    >  0 ,  where   2   denotes  a  Pareto  distribution
                     measure with the density  (dx) = 2α x  −( 2α+1)   (1,∞) (x)dx. In this case
                                                2
                     we have


                     where    =    if    >  0  and  + =  0  if    ≤  0 .  The  corresponding
                             +
                     generalized characteristic function is the Williamson transform (for more
                     details on the transform see, e.g., [14, 15, 16, 18])



                     Example 3. For every   ≥  2 and properly chosen   >  0 the function



                     is the kernel of a Kendall type (see [14]) generalized  convolution ⋄ defined
                     for  є [0,1] by the formula:



                      where λ1, λ2 are probability measures absolutely continuous with respect
                      to the Lebesgue measure and that does not depend on x. For example if
                              -1
                      c = (p-1)  then



                      and


                  It is natural to consider infinitely divisible measures with respect to generalized
                  convolutions.


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