  Dimitrov and Fioresi introduced an object that they call a generalized root
system. This is a finite set of vectors in a euclidean space satisfying certain
compatibilities between angles and sums and differences of elements. They
conjecture that every generalized root system is equivalent to one associated
to a restriction of a Weyl arrangement. In this note we prove the conjecture
and provide a complete classification of generalized root systems up to
equivalence.
