Accepting grammars and systems

We investigate several kinds of regulated rewriting (programmed, matrix, with regular control, ordered, and variants thereof) and of parallel rewriting mechanisms (Lindenmayer systems, uniformly limited Lindenmayer systems, limited Lindenmayer systems and scattered context grammars) as accepting devices, in contrast with the usual generating mode. In some cases, accepting mode turns out to be just as powerful as generating mode, e.g. within the grammars of the Chomsky hierarchy, within random context, regular control, L systems, uniformly limited L systems, scattered context. Most of these equivalences can be proved using a metatheorem on so-called context condition grammars. In case of matrix grammars and programmed grammars without appearance checking, a straightforward construction leads to the desired equivalence result. Interestingly, accepting devices are (strictly) more powerful than their generating counterparts in case of ordered grammars, programmed and matrix grammars with appearance checking (even programmed grammarsm with unconditional transfer), and 1lET0L systems. More precisely, if we admit erasing productions, we arrive at new characterizations of the recursivley enumerable languages, and if we do not admit them, we get new characterizations of the context-sensitive languages. Moreover, we supplement the published literature showing: - The emptiness and membership problems are recursivley solvable for generating ordered grammars, even if we admit erasing productions. - Uniformly limited propagating systems can be simulated by programmed grammars without erasing and without appearance checking, hence the emptiness and membership problems are recursively solvable for such systems. - We briefly discuss the degree of nondeterminism and the degree of synchronization for devices with limited parallelism

Analysis of Generative Chemistries

For the modelling of chemistry we use undirected, labelled graphs as explicit models of molecules and graph transformation rules for modelling generalised chemical reactions. This is used to define artificial chemistries on the level of individual bonds and atoms, where formal graph grammars implicitly represent large spaces of chemical compounds. We use a graph rewriting formalism, rooted in category theory, called the Double Pushout approach, which directly expresses the transition state of chemical reactions. Using concurrency theory for transformation rules, we define algorithms for the composition of rewrite rules in a chemically intuitive manner that enable automatic abstraction of the level of detail in chemical pathways. Based on this rule composition we define an algorithmic framework for generation of vast reaction networks for specific spaces of a given chemistry, while still maintaining the level of detail of the model down to the atomic level. The framework also allows for computation with graphs and graph grammars, which is utilised to model non-trivial chemical systems. The graph generation relies on graph isomorphism testing, and we review the general individualisation-refinement paradigm used in the state-of-the-art algorithms for graph canonicalisation, isomorphism testing, and automorphism discovery. We present a model for chemical pathways based on a generalisation of network flows from ordinary directed graphs to directed hypergraphs. The model allows for reasoning about the flow of individual molecules in general pathways, and the introduction of chemically motivated routing constraints. It further provides the foundation for defining specialised pathway motifs, which is illustrated by defining necessary topological constraints for both catalytic and autocatalytic pathways. We also prove that central types of pathway questions are NP-complete, even for restricted classes of reaction networks. The complete pathway model, including constraints for catalytic and autocatalytic pathways, is implemented using integer linear programming. This implementation is used in a tree search method to enumerate both optimal and near-optimal pathway solutions. The formal methods are applied to multiple chemical systems: the enzyme catalysed beta-lactamase reaction, variations of the glycolysis pathway, and the formose process. In each of these systems we use rule composition to abstract pathways and calculate traces for isotope labelled carbon atoms. The pathway model is used to automatically enumerate alternative non-oxidative glycolysis pathways, and enumerate thousands of candidates for autocatalytic pathways in the formose process

PROGRAMMING LANGUAGES À LA CARTE

Code reuse in computer language development is an open research problem. Feature-oriented programming is a vision of computer programming in which features can be implemented separately, and then combined to build a variety of software products; the idea of combining feature orientation and language development is relatively recent. Many frameworks for modular language development have been proposed during the years, but, although there is a strong connection between modularity and feature-orientation development, only few of these frameworks provide primitives to combine these two concepts. This work presents a model of modular language development that is directed towards feature orientation. We describe its implementation in the Neverlang framework. The model has been evaluated through several experiences: among the others, we present a code generator for a state machine language, that we use as a means to compare to other state-of-the-art frameworks, and a JavaScript interpreter implementation that further illustrates the capabilities of our solution

Chomskyan (R)evolutions

It is not unusual for contemporary linguists to claim that “Modern Linguistics began in 1957” (with the publication of Noam Chomsky’s Syntactic Structures). Some of the essays in Chomskyan (R)evolutions examine the sources, the nature and the extent of the theoretical changes Chomsky introduced in the 1950s. Other contributions explore the key concepts and disciplinary alliances that have evolved considerably over the past sixty years, such as the meanings given for “Universal Grammar”, the relationship of Chomskyan linguistics to other disciplines (Cognitive Science, Psychology, Evolutionary Biology), and the interactions between mainstream Chomskyan linguistics and other linguistic theories active in the late 20th century: Functionalism, Generative Semantics and Relational Grammar. The broad understanding of the recent history of linguistics points the way towards new directions and methods that linguistics can pursue in the future

The signification of speech and writing in the work of Charles Dickens

Drawing upon the work of Mikhail Bakhtin and Jacques Derrida, this study examines the representation of speech and writing in selected novels and journalism of Charles Dickens. The initial chapter describes the differing attitudes of Bakhtin and Derrida to language, writing and literature. A purely literary history is rejected, in favour of asking socially and historically grounded questions about the workings of language in selected texts. Then, the communication model of language, proposed by Roman Jakobson is examined. The theories of Derrida and Bakhtin are probed as alternative conceptualisations of the social process of language and textuality. The Jakobsonian model of language as a code common to all is rejected, and language is seen as 'heteroglossia' a collection of diverse voices. Bakhtin's focus on dialogue and the social context of utterance is balanced by Derrida's stress on writing as a textuality in which there is no dialogue of voices. Informed by these ideas, the remaining chapters explore the diversity of languages and ways of representing speech and writing in Dickens. The social shibboleths of language, the misspellings, bad grammar, puns, misunderstandings and noncommunication found in Dickens are explored. Several varieties of language are examined, thieves' cant, legal language, boxing and that of grammar itself. Each is represented and parodied by Dickens. Heteroglossia is then seen to have penetrated the most personal aspect of language, that of human names. Finally, reading and writing themselves are explored as themes within Dickens' work. The historical context of literacy in Victorian England is related to Dickens's concerns. Dickens is shown to have closely observed the transition from oral to literate culture in which writing communicates in the absence of the author. His frequently humourous ways of signifying speech and writing was also a means of social comment

Let us have articles betwixt us: Papers in Historical and Comparative Linguistics in Honour of Johanna L. Wood

Papers in Historical and Comparative Linguistics in Honour of Johanna L. Woo

Third International Conference on Technologies for Music Notation and Representation TENOR 2017

The third International Conference on Technologies for Music Notation and Representation seeks to focus on a set of specific research issues associated with Music Notation that were elaborated at the first two editions of TENOR in Paris and Cambridge. The theme of the conference is vocal music, whereas the pre-conference workshops focus on innovative technological approaches to music notation

On some one-sided dynamics of cellular automata

A dynamical system consists of a space of all possible world states and a transformation of said space. Cellular automata are dynamical systems where the space is a set of one- or two-way infinite symbol sequences and the transformation is defined by a homogenous local rule. In the setting of cellular automata, the geometry of the underlying space allows one to define one-sided variants of some dynamical properties; this thesis considers some such one-sided dynamics of cellular automata. One main topic are the dynamical concepts of expansivity and that of pseudo-orbit tracing property. Expansivity is a strong form of sensitivity to the initial conditions while pseudo-orbit tracing property is a type of approximability. For cellular automata we define one-sided variants of both of these concepts. We give some examples of cellular automata with these properties and prove, for example, that right-expansive cellular automata are chain-mixing. We also show that left-sided pseudo-orbit tracing property together with right-sided expansivity imply that a cellular automaton has the pseudo-orbit tracing property. Another main topic is conjugacy. Two dynamical systems are conjugate if, in a dynamical sense, they are the same system. We show that for one-sided cellular automata conjugacy is undecidable. In fact the result is stronger and shows that the relations of being a factor or a susbsystem are undecidable, too