This book offers a comprehensive treatment of the classical decision problem of mathematical logic and of the role of the classical decision problem in modern computer science. The text presents a revealing analysis of the natural order of decidable and undecidable cases and includes a number of simple proofs and exercises.

The theme of this book is formed by a pair of concepts: the concept of formal language as carrier of the precise expression of meaning, facts and problems, and the concept of algorithm or calculus, i.e. a formally operating procedure for the solution of precisely described questions and problems. The book is a unified introduction to the modern theory of these concepts, to the way in which they developed first in mathematical logic and computability theory and later in automata theory, (...) and to the theory of formal languages and complexity theory. Apart from considering the fundamental themes and classical aspects of these areas, the subject matter has been selected to give priority throughout to the new aspects of traditional questions, results and methods which have developed from the needs or knowledge of computer science and particularly of complexity theory. It is both a textbook for introductory courses in the above-mentioned disciplines as well as a monograph in which further results of new research are systematically presented and where an attempt is made to make explicit the connections and analogies between a variety of concepts and constructions. (shrink)

There is sufficient evidence from more recent experiments in psychology that equal retinal stimulus-elements do not lead to equal experiences and reactions except under certain rather specific conditions. An unsophisticated observer will find himself surprised to be able to cover with his own finger a person entering the door of his living room. When the finger is moved to the right or left, thus doing away with the precise retinal coincidence with the person, the observer will soon become unable to (...) recognize intuitively the actual retinal stimulus equality of the two distant things. This usually holds even for the case when he is making every inner effort towards an antagonistic, analytic perceptual attitude of the type which is used by painters or draughtsmen in order to represent the environmental situation in a similar way as it would project itself on a photographic plate or on a retina. (shrink)

Die nunmehr unter dem Namen der neuen Autoren Christian Armbrüster, Nicola Preuß und Thomas Renner erscheinende 5. Auflage des von Diether Huhn und Hans-Joachim von Schuckmann begründeten Kommentars zum Beurkundungsgesetz berücksichtigt: die Gesetzesänderungen zur Vorsorgevollmacht und zu elektronischen Zeugnissen ; die aktuelle BGH-Rechtsprechung zu Voraussetzungen und Reichweite der notariellen Belehrungspflichten; die neuesten Entwicklungen zur notariellen Tätigkeit mit Auslandsbezug und zum elektronischen Rechtsverkehr sowie insbesondere die Änderungen durch das MoMiG. Neben dem Beurkundungsgesetz und der Dienstordnung für Notarinnen und Notare enthält (...) der Kommentar die Bedingungen für Anderkonten und Anderdepots von Notaren und die Benachrichtigung in Nachlasssachen. Der Anhang zum Internationalen Urkundsverkehr umfaßt: Gutachten zum internationalen und ausländischen Privatrecht, Haager Postille, Anerkennung deutscher notarieller Urkunden im Ausland. Mit dem Armbrüster/Preuß/Renner liegt nun wieder eine geschlossene und praxisbezogene Darstellung auf neuestem Stand vor. (shrink)

This article raises the question of whether standard economics with the general equilibrium model at its core applies situational analysis in a Popperian sense. Contrary to Popper's own view, the authors come to the conclusion that this is not the case. Standard economics fails to represent elements essential to any social situation in an adequate manner. It comprises uncertainty, time and space, social interaction, unintended effects, as well as culture and institutions. The authors suggest, therefore, the socioeconomic context as an (...) alternative approach to analyzing social situations. It consists of four basic elements: (1) dominant worldviews, (2) institutions and technologies, (3) relative prices, and (4) political instruments. The alternative approach was applied with some success to analyzing inter alia problems of unemployment as well as of transformation. (shrink)

The differentiation of trait anxiety and depression in nonclinical and clinical populations is addressed. Following the tripartite model, it is assumed that anxiety and depression share a large portion of negative affectivity, but differ with respect to bodily hyperarousal and anhedonia. In contrast to the tripartite model, NA is subdivided into worry and dysthymia, which leads to a four-variable model of anxiety and depression encompassing emotionality, worry, dysthymia, and anhedonia. Item-level confirmatory factor analyses and latent class cluster analysis based on (...) a large nation-wide representative German sample substantiate the construct validity of the model. Further evidence concerning convergent and discriminant validity with respect to related constructs is obtained in two smaller nonclinical and clinical samples. Factors influencing the association between components of anxiety and depression are discussed. (shrink)

H. sapiens stands out from other primates along many social dimensions; however, none seems as prominent and important as the capacity of our species for cumulative cultural evolution or, as Tomasello calls it, “the ratchet.” Although other primate species show evidence of cultural variation, there is little evidence of cumulative cultural evolution, i.e., the gradual accumulation, modification, and refinement of traditions and skills over historical time, in any primate species other than our own. This is clearly an extremely significant component (...) of the human phenotype, responsible for our unparalleled cultural, social, political, and technological achievements. However, it remains extremely controversial what sorts of cognitive capacities are necessary to trigger cumulative cultural evolution and whether any currently proposed candidates are really distinctive of humans. Furthermore, the ratchet raises a bootstrapping problem: before complex skills and technologies are present and necessary for biological success, there appear to be few advantages to high-fidelity social learning; however, without such high-fidelity social learning, it is unclear how traditions capable of generating complex skills and technologies could arise in the first place. In this chapter, we survey relevant empirical research in comparative and developmental psychology, integrating it with a novel theoretical analysis of the bootstrapping problem to defend a hypothesis about the minimal cognitive preconditions on the ratchet. (shrink)