... (2007), #N23 7 A note on a problem of Hilliker and StrausMiroslawa Ja´nczakFaculty of Mathematics and CSAdam Mickiewicz Universityul. Umultowska 87, 61-614 Pozna´n, Polandmjanczak@amu.edu.plSubmitted: ... estimate the cardinality of A − B, where A is such that every element of A + A has at least two representations, and B is an arbitrary subset of Zp. The mainresult of this section can be stated ... 3.Observe that a i+1< a ifor all i and a i+1= a i/(2k−1) for all except at most one out of everym+1 consecutive terms a j, a j+1, . . . , a j+m. We have also a j+1≤ a j/k if a j+1= (a j−rj)/k,where...