A UTP semantics for communicating processes with shared variables

• Main Authors: SHI, Ling, ZHAO, Yongxin, LIU, Yang, SUN, Jun, DONG, Jin Song, QIN, Shengchao
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 2013
• Subjects: Shared Variable; Open Semantic; Parallel Composition; Sequential Program; Communicate Sequential Process; Software Engineering
• Online Access: https://ink.library.smu.edu.sg/sis_research/4999; https://ink.library.smu.edu.sg/context/sis_research/article/6002/viewcontent/a_utp.pdf
• Institution: Singapore Management University

CSP# (Communicating Sequential Programs) is a modelling language designed for specifying concurrent systems by integrating CSP-like compositional operators with sequential programs updating shared variables. In this paper, we define an observation-oriented denotational semantics in an open environment for the CSP# language based on the UTP framework. To deal with shared variables, we lift traditional event-based traces into hybrid traces which consist of event-state pairs for recording process behaviours. We also define refinement to check process equivalence and present a set of algebraic laws which are established based on our denotational semantics. Our approach thus provides a rigorous means for reasoning about the correctness of CSP# process behaviours. We further derive a closed semantics by focusing on special types of hybrid traces; this closed semantics can be linked with existing CSP# operational semantics.