COUNTING SUMSETS AND DIFFERENCES IN ABELIAN GROUP
Subset A of a group G is called (k, l)-sumset, if A = kB - lB for some B  G, where kB - lB = {x <sub>1</sub> + ∙∙∙ + x <sub>k</sub> - x <sub>k+1</sub>- ∙∙∙ - x <sub>k+l</sub> | x <sub>1</sub>,...,x <sub>k+1 </sub> ∈ B}. Upper and lower bounds for the numbers of (1,1)-sumsets and (2,0)-sumsets in abelian groups are provided.