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P9326   J.C.M. Baeten & J.A. Bergstra
        "Non interleaving process algebra"


We study a non-interleaving subalgebra of a reduct of a model of ACP. The
model discussed uses step bisimulation semantics. We can derive identities
in this model with the help of the (interleaving) ACP calculus with
multi-actions. We study the connection with Petri nets, and introduce
causalities and a causal state operator.