π-calculus, Session Types research at Imperial College

The pi-calculus is a widely used process calculus, which models communications between processes and allows the passing of communication links. Various operational semantics of the pi-calculus have been proposed, which can be classified according to whether transitions are unlabelled (so-called reductions) or labelled. With labelled transitions, we can distinguish early and late semantics.

The early version allows a process to receive names it already knows from the environment, while the late semantics and reduction semantics do not. All existing reversible versions of the π-calculus use reduction or late semantics, despite the early semantics of the (forward-only) π-calculus being more widely used than the late. We define piIH, the first reversible early pi-calculus, and give it a denotational semantics in terms of reversible bundle event structures. The new calculus is a reversible form of the internal π-calculus, which is a subset of the pi-calculus where every link sent by an output is private, yielding greater symmetry between inputs and outputs.

@inproceedings{GPY2020, author = {Eva Graversen and Iain Phillips and Nobuko Yoshida}, title = {{Event Structures for the Reversible Early Internal Pi-Calculus}}, booktitle = {12th Conference on Reversible Computation}, series = {LNCS}, pages = {--}, publisher = {Springer}, year = 2020 }

@inproceedings{GPY2020, author = {Eva Graversen and Iain Phillips and Nobuko Yoshida}, title = {{Event Structures for the Reversible Early Internal Pi-Calculus}}, booktitle = {12th Conference on Reversible Computation}, series = {LNCS}, pages = {--}, publisher = {Springer}, year = 2020 }