  Given an integer $k \geq 2$ and a real number $\gamma\in [0, 1]$, which
graphs of edge density $\gamma$ contain the largest number of $k$-edge stars?
For $k=2$ Ahlswede and Katona proved that asymptotically there cannot be more
such stars than in a clique or in the complement of a clique (depending on the
value of $\gamma$). Here we extend their result to all integers $k\ge 2$.
