W. P. de Roever

on Linear time, branching time and partial order in logics and models for concurrency

Time, logic and computation.- Process theory based on bisimulation semantics.- Branching time temporal logic.- Observing processes.- The anchored version of the temporal framework.- Basic notions of trace theory.- An introduction to event structures.- A logic for the description of behaviours and properties of concurrent systems.- Permutation of transitions: An event structure semantics for CCS and SCCS.- Expressibility results for linear-time and branching-time logics.- Partial orderings descriptions and observations of nondeterministic concurrent processes.- Modeling concurrency by partial orders and nonlinear transition systems.- An efficient verification method for parallel and distributed programs.- A logic for distributed transition systems.- Fully abstract models for a process language with refinement.- Strong bisimilarity on nets: A new concept for comparing net semantics.- Nets of processes and data flow.- Towards a temporal logic for causality and choice in distributed systems.- Correctness and full abstraction of metric semantics for concurrency.- Temporal logics for CCS.- Behavioural presentations.- Computation tree logic and regular ?-languages.

The m-calculus as an assertion-language for fairness arguments

Abstract Various principles of proof have been proposed to reason about fairness. This paper addresses—for the first time—the question in what formalism such fairness arguments can be couched. To wit: we prove that Parks monotone first-order μ-calculus, augmented with constants for all recursive ordinals can serve as an assertion-language for proving fair termination of do-loops. In particular, the weakest precondition for fair termination of a loop w.r.t. some postcondition is definable in it. The relevance of this result to proving eventualities in the temporal logic formalism of Manna and Pnuelis ( in “Foundations of Computer Science IV, Part 2,” Math. Centre Tracts, Vol. 159, Math. Centrum, Amsterdam, 1983) is discussed.

Designing distributed algorithms by means of formal sequentially phased reasoning

Designers of network algorithms give elegant informal descriptions of the intuition behind their algorithms (see [GHS83, Hu83, MS79, Se82, Se83, ZS80]). Usually, these descriptions are structured as if tasks or subtasks are performed sequentially. From an operational point of view, however, they are performed concurrently. Here, we present a design principle that formally describes how to develop algorithms according to such sequentially phased explanations. The design principle is formulated using Manna and Pnuelis linear time temporal logic [MP83]. This principle, together with Chandy and Misras technique [CM88] or Back and Seres technique [BS89] for designing parallel algorithms, is applicable to large classes of algorithms, such as those for minimum-path, connectivity, network flow, and minimum-weight spanning trees. In particular, the distributed minimum-weight spanning tree algorithm of Gallager, Humblet, and Spira [GHS83] is structured according to our principle.

Foundations of Object-Oriented Languages

A report on the workshop Foundations of ObjectOriented Languages, Paris, July 1994.