A few remarks on quadratic harnesses
  We analyze and partially solve system of recurrences that can be derived from the properties of martingale orthogonal polynomials that characterize quadratic harnesses (QH). We also specify conditions for the existence of moments of one dimensional distribution for large classes of quadratic harnesses that are also Markov processes complementing earlier results. 
Pawe{\l} J. Szab{\l}owski
math.PR math.CA