  Heterogeneous nonmonotonic multi-context systems (MCS) permit different
logics to be used in different contexts, and link them via bridge rules. We
investigate the role of symmetry detection and symmetry breaking in such
systems to eliminate symmetric parts of the search space and, thereby, simplify
the evaluation process. We propose a distributed algorithm that takes a local
stance, i.e., computes independently the partial symmetries of a context and,
in order to construct potential symmetries of the whole, combines them with
those partial symmetries returned by neighbouring contexts. We prove the
correctness of our methods. We instantiate such symmetry detection and symmetry
breaking in a multi-context system with contexts that use answer set programs,
and demonstrate computational benefit on some recently proposed benchmarks.
