  Fuzzy structures such as fuzzy automata, fuzzy transition systems, weighted
social networks and fuzzy interpretations in fuzzy description logics have been
widely studied. For such structures, bisimulation is a natural notion for
characterizing indiscernibility between states or individuals. There are two
kinds of bisimulations for fuzzy structures: crisp bisimulations and fuzzy
bisimulations. While the latter fits to the fuzzy paradigm, the former has also
attracted attention due to the application of crisp equivalence relations, for
example, in minimizing structures. Bisimulations can be formulated for fuzzy
labeled graphs and then adapted to other fuzzy structures. In this article, we
present an efficient algorithm for computing the partition corresponding to the
largest crisp bisimulation of a given finite fuzzy labeled graph. Its
complexity is of order $O((m\log{l} + n)\log{n})$, where $n$, $m$ and $l$ are
the number of vertices, the number of nonzero edges and the number of different
fuzzy degrees of edges of the input graph, respectively. We also study a
similar problem for the setting with counting successors, which corresponds to
the case with qualified number restrictions in description logics and graded
modalities in modal logics. In particular, we provide an efficient algorithm
with the complexity $O((m\log{m} + n)\log{n})$ for the considered problem in
that setting.
