2022/05/13 by Fang, Jin-Hui, Sándor, Csaba
#FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.2205.06553
For nonempty sets A,B of nonnegative integers and an integer n, let rA,B(n) be the number of representations of n as a+b and dA,B(n) be the number of representations of n as a-b, where a∈ A, b∈ B. In this paper, we determine the sets A,B such that rA,B(n)=1 for every nonnegative integer n. We also consider the difference structure and prove that: there exist sets A and B of nonnegative integers such that rA,B(n)≥ 1 for all large n, A(x)B(x)=(1+o(1))x and for any given nonnegative integer c, we have dA,B(n)=c for infinitely many positive integers n. Other related results are also contained.