  We present a generic partition refinement algorithm that quotients
coalgebraic systems by behavioural equivalence, an important task in reactive
verification; coalgebraic generality implies in particular that we cover not
only classical relational systems but also various forms of weighted systems.
Under assumptions on the type functor that allow representing its finite
coalgebras in terms of nodes and edges, our algorithm runs in time
$\mathcal{O}(m\cdot \log n)$ where $n$ and $m$ are the numbers of nodes and
edges, respectively. Instances of our generic algorithm thus match the runtime
of the best known algorithms for unlabelled transition systems, Markov chains,
and deterministic automata (with fixed alphabets), and improve the best known
algorithms for Segala systems.
