  The well known Hopcroft's algorithm to minimize deterministic complete
automata runs in $O(kn\log n)$-time, where $k$ is the size of the alphabet and
$n$ the number of states. The main part of this algorithm corresponds to the
computation of a coarsest bisimulation over a finite Deterministic Labelled
Transition System (DLTS). By applying techniques we have developed in the case
of simulations, we design a new algorithm which computes the coarsest
bisimulation over a finite DLTS in $O(m\log n)$-time and $O(k+m+n)$-space, with
$m$ the number of transitions. The underlying DLTS does not need to be complete
and thus: $m\leq kn$. This new algorithm is much simpler than the two others
found in the literature.
