Real line arrangements with Hirzebruch property
  A line arrangement of $3n$ lines in $\mathbb CP^2$ satisfies Hirzebruch property if each line intersect others in $n+1$ points. Hirzebruch asked if all such arrangements are related to finite complex reflection groups. We give a positive answer to this question in the case when the line arrangement in $\mathbb CP^2$ is real, confirming that there exist exactly four such arrangements. 
Dmitri Panov
math.AG math.CO math.DG math.GT