Nondeterminism

Girard’s linear logic has been previously applied to functional programming for performing state-manipulation and controlling storage reuse. These applications only use intuitionistic linear logic, the subset of linear logic that embeds intuitionistic logic. Full linear logic (called classical linear logic) is much richer than this subset. In this paper, we consider the application of classical linear logic to functional programming. The negative types of linear logic are interpreted as denoting acceptors. An acceptor is an entity which takes an input of some type and returns no output. Acceptors generalize continuations and also single assignment variables, as found in data flow languages and logic programming languages. The parallel disjunction operator allows such acceptors to be used in a nontrivial fashion. Finally, the “why not” operator of linear logic gives rise to nondeterministic values. We define a typed functional language based on the these ideas and demonstrate its use...

Interactive storytelling is a new kind of digital entertainment in which users interact with a story being told. In this context, automated planning algorithms are interesting alternatives to create plots that are coherent with the intended genre. Diversity of stories and opportunities for interaction are however other key requirements to be considered by such applications. It is also important to generate stories incorporating failed attempts to achieve goals, since this is essential to create dramatic tension. In this paper, we describe a planner that takes these issues into account by means of planning with nondeterministic events, that is, events with more than one possible different outcome. The implemented planner has been incorporated to the new version of the interactive storytelling system Logtell.

ABSTRACT The ø-angelic choice is an operator that captures the behaviour of the external choice of CSP in a branching time setting. The idea of the ø-angelic choice is to delay any choice until an observable action happens. In this way, this new operator avoids preemption introduced by internal actions (ø actions). It is studied in theories with abstraction, more precisely, branching bisimulation and ø-bisimulation. In addition, an ilustrative example of application is given. Keywords: theory of concurrency, semantics of reactive systems, process algebra, nondeterminism, specification and verification methodologies 1 Introduction Process algebras [BW90] aim to deal with Semantic of Reactive Systems [Pnu85]. These systems, whose classical examples are industrial control systems, drivers of computer networks, components of operating systems or protocols of comunication, are mainly characterized by the fact that they can be described as maintaining an interaction with their environment. It is no...