We extend positive supercompilation to handle negative as well as positive information. This is done by instrumenting the underlying unfold rules with a small rewrite system that handles constraints on terms, thereby ensuring perfect information propagation. We illustrate this by transforming a naively specialised string matcher into an optimal one. The presented algorithm is guaranteed to terminate by means of generalisation steps.

This paper gives a gentle introduction to Turchin's supercompilation and its applications in metacomputation with an emphasis on recent developments. First, a complete supercompiler, including positive driving and generalization, is defined for a functional language and illustrated with examples. Then a taxonomy of related transformers is given and compared to the supercompiler. Finally, we put supercompilation into the larger perspective of metacomputation and consider three metacomputation tasks: specialization, composition, and inversion.

Turchin`s supercompiler is a program transformer that includes both partial evaluation and deforestation. Although known in the West since 1979, the essence of its techniques, its more precise relations to other transformers, and the properties of the programs that it produces are only now becoming apparent in the Western functional programming community. This thesis gives a new formulation of the supercompiler in familiar terms; we study the essence of it, how it achieves its effects, and its relations to related transformers; and we develop results dealing with the problems of preserving semantics, assessing the efficiency of transformed programs, and ensuring termination.

We consider the principle "a new model is a model of an existing one" as the main scheme for deriving new linguistic models by metacomputation. We derive the basic requirements for metacomputation by a structural analysis of different model definitions, and show that in order to automate the creation of linguistic models the following operations on linguistic models have to be performed by metacomputation effectively and efficiently: composition, inversion, and specialization of algorithms. This may also serve as a unifying paradigm for different program transformation approaches. 1. INTRODUCTION During the last decades we have witnessed tremendous technological breakthroughs in the development and application of computers. The introduction of the computer was an evolutionary step in the control of formal linguistic models, a metasystem transition (MST). As a result the number of linguistic models created and used has significantly increased. The method of modern science is, in its e...

The Principia Cybernetica Project was created to develop an integrated philosophy or world view, based on the theories of evolution, selforganization, systems and cybernetics. Its conceptual network has been implemented as an extensive website. The present paper reviews the assumptions behind the project, focusing on its rationale, its philosophical presuppositions, and its concrete methodology for computer-supported collaborative development. Principia Cybernetica starts from a process ontology, where a sequence of elementary actions produces ever more complex forms of organization through the mechanism of variation and selection, and metasystem transition. Its epistemology is constructivist and evolutionary: models are constructed by subjects for their own purposes, but undergo selection by the environment. Its ethics takes fitness and the continuation of evolution as the basic value, and derives more concrete guidelines from this implicit purpose. Together, these postulates and their implications provide answers to a range of age-old philosophical questions.

The principle of natural selection is taken as a starting point for an analysis of evolutionary levels. Knowledge and values are conceived as vicarious selectors of actions from a repertoire. The concept of metasystem transition is derived from the law of requisite variety and the principle of hierarchy. It is defined as the increase of variety at the object level, accompanied by the emergence of a situation-dependent control at a metalevel. It produces a new level of evolution, with a much higher capacity for adaptation. The most important levels are discussed, with an emphasis on the level characterizing man as distinct from the animals. An analysis of the shortcomings of this "rational" system of cognition leads to a first sketch of how the next higher "meta-rational" level would look like.

We study the structure of language hierarchies and their reduction by two forms of metacomputation in order to overcome the time and space complexity of language hierarchies. We show that program specialization and program composition are sufficient to reduce all forms of language hierarchies constructed from interpreters and translators. We argue that the reduction of language hierarchies is a prerequisite for effective formal linguistic modeling on a large scale. 1 Introduction One of the defining features of modern science is the use of languages, both informal and formal, to construct linguistic models of reality [8]. The introduction of the computer was a revolutionary step in the execution of formal linguistic models and, as a result, the number of linguistic models created and used has significantly increased in all branches of science during the last decades. Computer science, as we see it, is laying the foundations and developing the research paradigm and scientific me...

this article, who are responsible for implementation of the system and the collection and development of the material. Similar to a journal, it may rely on an Editorial Advisory Board, and other associated editors, referees, and contributors. The editors are actively looking for like-minded researchers to participate in the Project. Thus Principia Cybernetica is seen as necessarily open ended and developing, essentially a process of discourse among a community of researchers. A variety of collaboratory granularities are possible, ranging from contributions by individual authors, through groups of authors, to consensual statements of all project participants. Participants are free to develop their material within Principia Cybernetica while having it simultaneously available for traditional publications. Copyright is initially held by Principia Cybernetica,

An extension of Turchin’s supercompilation from functional to object-oriented languages as it is implemented in the current version of a Java supercompiler (JScp) is reviewed. There are two novelties: first, the construction of the specialized code of operations on objects is separated into two stages—residualization of all operations on objects during supercompilation proper and elimination of redundant code in post-processing; and second, limited configuration analysis, which processes each Java control statement one by one using width-first unfolding of a process graph, is used. The construction of JScp is based on the principle of user control of the process of supercompilation rather than building a black-box automatic supercompiler. The rationale for this decision is discussed.

(selfreproduction and self-maintenance, used in the context of biological systems) of Maturana and Varela [37] forms just a preliminary climax in this field. In addition to these concepts, evolutionary methods for the generation of complex systemic relationships play an important role in trying to describe and understand the behaviour of natural systems. Striking success in the application of evolutionistic procedures, e.g. for the generation of very complex motion patterns, were made by C. Langton in the scientific research area of artificial life founded by him [31]. In this context we have to mention the "Principia Cybernatica Projects" which aims at the generation of an evolutionistic-systemic worldview (Heylighen, Joslyn, Turchin [25, 15, 18, 48]). Especially their success in the generalisation of the evolution theory and the "Metasystem Transition Theory" [48] to explain the emergence of complexity should be mentioned. Here the concept of hierarchy plays an important role. Turch