We study the use of the-calculus for semantical descriptions of higher-order concurrent languages with state. As an example, we choose Concurrent Idealized ALGOL (CIA). CIA is particularly interesting as, yet being a core language, it combines imperative and parallel features with a procedural mechanism of full higher order. It can thus be used as a formal model for concurrent programs as, e.g....

We explain how recent developments in game semantics can be applied to reasoning about equivalence of terms in a non-trivial fragment of Idealized Algol (IA) by expressing sets of complete plays as regular languages. Being derived directly from the fully abstract game semantics for IA, our model inherits its good theoretical properties; in fact, for second-order IA taken as a stand-alone langua...

The analysis of the available data allows to conclude that changes of the orbital periods in both Algol-type systems, SW Cyg and U Sge, are correlated with the brightness variations of the late-type loser. The episodes of decrease of the orbital period are accompanied by minimum of brightness of the loser in both cases.

Using game semantics, we prove a full abstraction result (with respect to the may-testing preorder) for Idealized Algol augmented with parallel composition (IA). Although it is common knowledge that semaphores can be implemented using shared memory, we find that semaphores do not extend IA conservatively. We explain the reasons for the mismatch.

In this paper, we present a new model of class-based Algollike programming languages inspired by automata-theoretic concepts. The model may be seen as a variant of the ”object-based” model previously proposed by Reddy, where objects are described by their observable behaviour in terms of events. At the same time, it also reflects the intuitions behind state-based models studied by Reynolds, Ole...