Minimal Session Types (Pearl)

Minimal Session Types for the π-calculus (Extended Version)

“…Because sequentiality is so useful for protocol specification and verification, a natural question is whether it could be recovered by other means. To this end, Arslanagić et al [1] defined MSTs as the sub-class of session types without the ' ; ' construct. They established a minimality result: every well-typed session process can be decomposed into a process typable with MSTs.…”

“…The minimality result in [1] holds for a higher-order process calculus called HO, in which values are only abstractions (functions from names to processes). HO does not include name passing nor process recursion, but it can encode them precisely [8,10].…”

“…HO does not include name passing nor process recursion, but it can encode them precisely [8,10]. An important question left open in [1] is whether the minimality result holds for the session -calculus (dubbed ), the language in which values are names and for which session types have been more widely studied from foundational and practical perspectives.…”

“…Our approach is simple, perhaps even deceptively so. In order to establish the minimality result for , we compose the decomposition in [1] with the mutual encodings between HO and given in [8,10]. HO HO Let and HO denote the process languages and HO with MSTs (rather than with standard session types).…”

“…HO HO Let and HO denote the process languages and HO with MSTs (rather than with standard session types). Also, let D (•) denote the decomposition function from HO to HO defined in [1]. Kouzapas et al [8,10] gave typed encodings from to HO (denoted • 1 ) and from HO to (denoted • 2 ).…”