Acta Informatica

, Volume 28, Issue 5, pp 447–452 | Cite as

The expressive power of delay operators in SCCS

  • Carol Critchlow
  • Prakash Panangaden


We investigate the relative expressive power of finite delay operators in SCCS. These were introduced by Milner and by Hennessy to study fairness properties of processes in the context of SCCS. We show that the context sensitive delay operator introduced by Hennessy is more expressive than the finite delay operator introduced by Milner. This result is closely related to recent results by Pananagden and Stark on the expressive power of fair merge in asynchronous dataflow (Kahn) networks. It indicates that the expressiveness results obtained there are not sensitive to the precise computational model since SCCS, unlike Kahn networks, is synchronous and permits expansion of recursively defined processes.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Hennessy, M.: Axiomatizing finite delay operators. Acta Inf.21, 61–88 (1984)Google Scholar
  2. 2.
    Hennessy, M.: Algebraic theory of processes. Cambridge London: MIT Press 1988Google Scholar
  3. 3.
    Milner, R.: A finite-delay operator in synchronous ccs. Technical report CSR-116-82, University of Edinburgh, 1982Google Scholar
  4. 4.
    Milner, R.: Calculi for synchrony and asynchrony. Theor. Comput. Sci.25, 267–310 (1983)Google Scholar
  5. 5.
    Milner, R.: Communication and concurrency. Englewood Cliffs, NJ: Prentice-Hall 1989Google Scholar
  6. 6.
    Panangaden, P., Stark, E.W.: Computations, residuals and the power of indeterminacy. In: Lepisto, T., Salomaa, A. (eds.) Proceedings of the Fifteenth ICALP. (Lect. Notes Comput. Sci., vol. 317, pp. 439–454) Berlin Heidelberg New York: Springer 1988Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Carol Critchlow
    • 1
  • Prakash Panangaden
    • 2
  1. 1.Center for Applied MathematicsCornell UniversityIthacaUSA
  2. 2.Computer Science DepartmentCornell UniversityIthacaUSA

Personalised recommendations