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On the Relative Expressiveness of Higher-Order Session Processes

Dimitrios KOUZAPAS, Jorge A.PÉREZ, Nobuko YOSHIDA

By integrating constructs from the λ-calculus and the π-calculus, in higher-order process calculi exchanged values may contain processes. This paper studies the relative expressiveness of HOπ, the higher-order π-calculus in which communications are governed by session types. Our main discovery is that HO, a subcalculus of HOπ which lacks name-passing and recursion, can serve as a new core calculus for session-typed higher-order concurrency. We show that HO can encode HOπ fully abstractly (up to typed contextual equivalence) more precisely and efficiently than the first-order session π-calculus (π). Overall, under the discipline of session types, HOπ, HO, and π are equally expressive; however, we show that HOπ is more tightly related to HO than to π.

@article{KPY2019,
  author = {Dimitrios Kouzapas and Jorge A. Pérez and Nobuko Yoshida},
  title = {{On the Relative Expressiveness of Higher-Order Session Processes}},
  journal = {IC},
  pages = {1--54},
  publisher = {Elsevier},
  year = 2019
}

@article{KPY2019,
  author = {Dimitrios Kouzapas and Jorge A. Pérez and Nobuko Yoshida},
  title = {{On the Relative Expressiveness of Higher-Order Session Processes}},
  journal = {Information and Computation},
  pages = {1--54},
  publisher = {Elsevier},
  doi = "10.1016/j.ic.2019.06.002",
  year = 2019
}