Abstract:
A subset $A$ of a group $G$ is called $(k,l)$-sumset, if $A=kB-lB$ for some $B\subseteq G$, where $kB-lB=\{x_1+\dots+x_k-x_{k+1}-\dots-x_{k+l}\mid x_1,\dots,x_{k+l}\in B\}$. Upper and lower bounds for the numbers of $(1,1)$-sumsets and $(2,0)$-sumsets in abelian groups are provided. Bibliogr. 4.