A superadditivity and submultiplicativity property for cardinalities of sumsets

Katalin Gyarmati, Imre Z. Ruzsa, Mate Matolcsi

For finite sets of integers $A_1,A_2...A_n$ we study the cardinality of the $n$-fold sumset $A_1+...+A_n$ compared to those of $n-1$-fold sumsets $A_1+... +A_{i-1}+A_{i+1}+...…