A notion of open bisimulation is formulated for the spi calculus, an extension of the π-calculus with cryptographic primitives. This notion of open bisimulation is based on the so-called hedged bisimulation, due to Borgström and Nestmann. Open bisimulation is shown to be sound with respect to hedged bisimulation, and futher, open bisimilarity is shown to be a congruence relation on finite spi p...

The F&B-index is used to speed up pattern matching in tree and graph data, and is based on the maximum F&B-bisimulation, which can be computed in loglinear time for graphs. It has been shown that the maximum F-bisimulation can be computed in linear time for DAGs. We build on this result, and introduce a linear algorithm for computing the maximum F&B-bisimulation for tree data. It first computes...