Decidability and the Entscheidungsproblem

2017 ◽  
Author(s):  
Robin Whitty
Keyword(s):  
Mathematical Model ◽  
Computer Science ◽  
20Th Century ◽  
Turing Machine ◽  
Human Computation ◽  
Early 20Th Century ◽  
Binary Representation ◽  
The Third ◽  
Alan Turing ◽  
Modern Computer

In 1936 Turing invented a mathematical model of computation, known today as the Turing machine. He intended it as a representation of human computation and in particular as a vehicle for refuting a central part of David Hilbert’s early 20th-century programme to mechanize mathematics. By a nice irony it came to define what is achievable by non-human computers and has become deeply embedded in modern computer science. A simple example is enough to convey the essentials of a Turing machine. We then describe the background to Hilbert’s programme and Turing’s challenge—and explain how Turing’s response to Hilbert resolves a host of related problems in mathematics and logic. If I had to portray, in less than 30 seconds, what Alan Turing achieved in 1936 it seems to me that drawing the picture shown in Fig. 37.1 would be a reasonable thing to do. That this might be so is a testament to the quite extraordinary merging of the concrete and the abstract in Turing’s 1936 paper on computability. It is regarded by, I suppose, a large majority of mathematical scientists as his greatest work. The details of our picture are not especially important. As it happens, it is a machine for deciding which whole numbers, written in binary form, are multiples of 3. It works thus: suppose the number is 105, whose binary representation is 1101001, because (1 × 26) + (1 × 25) + (0 × 24) + (1 × 23) + (0 × 22) + (0 × 21) + (1 × 20) = 64 + 32 + 8 + 1 = 105. We start at the node labelled A and use the binary digits to drive us from node to node. The first couple of 1s take us to node B and back to A again. The third digit, 0, loops us around at A. Now a 1 and a 0 take us across to node C; and the final 0 and 1 take us back via B to A once more.

The Universal Machine

2017 ◽  
Author(s):  
Arlindo Oliveira
Keyword(s):  
Computer Science ◽  
Turing Machine ◽  
Universal Machine ◽  
Alan Turing ◽  
Modern Computer ◽  
Basic Concepts ◽  
The Church

This chapter covers the development of computing, from its origins, with the analytical engine, to modern computer science. Babbage and Ada Lovelace’s contributions to the science of computing led, in time, to the idea of universal computers, proposed by Alan Turing. These universal computers, proposed by Turing, are conceptual devices that can compute anything that can possibly be computed. The basic concepts created by Turing and Church were further developed to create the edifice of modern computer science and, in particular, the concepts of algorithms, computability, and complexity, covered in this chapter. The chapter ends describing the Church-Turing thesis, which states that anything that can be computed can be computed by a Turing machine.

scholarly journals The Proposal of a Evolutionary Strategy Generating the Data Structures Based on a Horizontal Tree for the Tests

2016 ◽  
Vol 23 (3) ◽  
pp. 145-149
Author(s):  
Marek Żukowicz ◽  
Michał Markiewicz
Keyword(s):  
Mathematical Model ◽  
Evolutionary Algorithm ◽  
Computer Science ◽  
Data Structures ◽  
Evolutionary Strategy ◽  
Future Research ◽  
Object Model ◽  
The Third ◽  
Testing Data ◽  
Definition Of

Abstract The aim of the article is to present a mathematical definition of the object model, that is known in computer science as TreeList and to show application of this model for design evolutionary algorithm, that purpose is to generate structures based on this object. The first chapter introduces the reader to the problem of presenting data using the TreeList object. The second chapter describes the problem of testing data structures based on TreeList. The third one shows a mathematical model of the object TreeList and the parameters, used in determining the utility of structures created through this model and in evolutionary strategy, that generates these structures for testing purposes. The last chapter provides a brief summary and plans for future research related to the algorithm presented in the article.

scholarly journals Unrealism in russian prose of early 20th century

2020 ◽  
Vol 6 (Extra-C) ◽  
pp. 75-85
Author(s):  
Elena V. Astashchenko
Keyword(s):  
20Th Century ◽  
Social Pressure ◽  
General Concept ◽  
Early 20Th Century ◽  
Second Person ◽  
The Third ◽  
The Past ◽  
Third Person ◽  
The Third Person ◽  
Imperative Mood

  The aim of the article is to analyze the multilevel manifestation of the text modality - from grammatical to aesthetic and build a general concept of unrealism as a peripheral, but permanent, constant of the modernist era. However, the ubiquity and dominant delimitation, necessary of structures with conjunctions of unreal comparison, with the predominance of those derived from future forms over those derived from the imperfect, also serves to strengthen the independence of the artwork from social pressure. Subsequently, the characteristic structures of modernity, analogous to the European "future in the past", building an alternative reality, are supplanted by the imperative mood of the second person, with the illocutionary act of calling for a change in the existing reality, in the primitive vanguard and the third person with the "pust" particle [let] in the middle of the 20th century, gradually degenerating into the imperative mood with the "puskai" particle [May], whose motivating pathos is extremely low.  

scholarly journals THE EVOLUTION OF CINEMATOGRAPHY IN RUSSIAN LITERATURE OF THE 1920S

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Valentina A. Nikolaeva ◽  
Natalia L. Fesyanova ◽  
Olga N. Goryacheva
Keyword(s):  
20Th Century ◽  
Russian Literature ◽  
Early 20Th Century ◽  
Time And Space ◽  
Cultural Process ◽  
The Third ◽  
Main Emphasis ◽  
Close Relationship

This paper concerns the issue of the interaction of literature and cinematography in the cultural process of the 1920s. The main emphasis is placedon the phenomenon of literary cinematography, which became widespread in the third decade of the 20th century. The content of the concept of “cinematographic literature”is defined, its significant characteristics are singled out (special compositional-syntactic organization of the work, representation of the situation of observation, the use of cinema techniques) and the development of cinematography in the work of poets and writers of the period is studied. Inthecourseof the analysis of thetexts, specific techniques and cinematographic functions characteristic of this decade were singledout. Experimenting with artistic time and space, the authors attach an innovative character to the works, develop new ways of constructing the plot. In addition, cinematography makes it possible to add the text documentary and agitationality. The study revealed a close relationship between the development of cinematography in the literature and the general tendencies of the cultural process of the early 20th century.

Plurality and Diversity: The Profile of a Medieval Library

2016 ◽  
Author(s):  
Konrad Hirschler
Keyword(s):  
Incomplete Information ◽  
20Th Century ◽  
Early 20Th Century ◽  
Spatial Organisation ◽  
Alphabetical Order ◽  
The Third ◽  
Insight Into

The third chapter discusses one of the most intriguing aspects of this document, its system of ordering books. Our knowledge of medieval library systems has hitherto been confined to small collections and thus rudimentary systems or incomplete information in narrative sources. The chapter shows the highly-developed system for organising books according to three parameters, alphabetical order of titles, size of the books and their themes. In contrast to the highly philosophical schemes of how to organise and hierarchise the various learned branches of knowledge (such as those by al-Ghazali and al-Kindi) this library gives a very different insight into how knowledge was organised on a practitioner’s level. The organisation of the library, in addition to several other features of the catalogue, allows also an understanding of the spatial organisation of the library (the actual building was destroyed in the early 20th century). We do not have any study of the spatial aspects of a medieval Arabic library yet and the chapter offers the first exploration of this theme.

Generic Synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), Part I — Myrmicinae and Pseudomyrmecinae

Zootaxa ◽  
2011 ◽  
Vol 2878 (1) ◽  
pp. 1 ◽  
Author(s):  
KATSUYUKI EGUCHI ◽  
BUI TUAN VIET ◽  
SEIKI YAMANE
Keyword(s):  
20Th Century ◽  
Early Period ◽  
Early 20Th Century ◽  
New Genera ◽  
Systematic Treatment ◽  
Northern Vietnam ◽  
The Third ◽  
Higher Taxa ◽  
Infraspecific Taxa ◽  
American Authors

Alpha taxonomy of Vietnamese ants was initiated by European and American authors in the early 20th century, and approximately 160 species and infraspecific taxa were described or recorded in this early period. From 1965 to 1966 an inventory project of insects in northern Vietnam was conducted by the Agriculture Ministry of Vietnam, and 36 ant species were recorded. The identity of those taxa, however, needs to be revised based on the modern taxonomy of ants. Since theend of the 1980's dozens of ant species have been newly recorded or described from Vietnam. Regional revisions dealing with Vietnamese species have also been published for several genera including Myrmica, Probolomyrmex, Pheidole, Acanthomyrmex and Anillomyrma. Furthermore, two new genera, Parvimyrma (Myrmicinae) and Opamyrma (Amblyoponinae), were recently described from the country. However, there has been no comprehensive systematic treatment of the Vietnamese ants to date. In order to develop the taxonomy of ants in Vietnam, we have begun a program to: (1) explore local ant faunas; (2) give species codes to all species; (3) overview ant genera known from Vietnam; (4) describe unnamed taxa and review higher taxa known from Vietnam and adjacent areas. Ninety-two genera in twelve subfamilies have so far been recognized by us: DOLICHODERINAE: Chronoxenus, Dolichoderus, Iridomyrmex, Liometopum, Ochetellus, Philidris, Tapinoma, Technomyrmex; FORMICINAE: Acropyga, Anoplolepis, Camponotus, Cladomyrma, Echinopla, Gesomyrmex, Lasius, Lepisiota, Myrmoteras, Nylanderia, Oecophylla, Paratrechina, Paraparatrechina, Plagiolepis, Polyrhachis, Prenolepis, Pseudolasius, Undescribed genus "eg-2"; PSEUDOMYRMECINAE: Tetraponera; CERAPACHYINAE: Cerapachys, Simopone; AENICTINAE: Aenictus; DORYLINAE: Dorylus; LEPTANILLINAE: Leptanilla, Protanilla; AMBLYOPONINAE: Amblyopone, Myopopone, Mystrium, Opamyrma, Prionopelta; PONERINAE: Anochetus, Centromyrmex, Cryptopone, Diacamma, Harpegnathos, Hypoponera, Leptogenys, Odontomachus, Odontoponera, Pachycondyla, Platythyrea, Ponera; ECTATOMMINAE: Gnamptogenys; PROCERATIINAE: Discothyrea, Probolomyrmex, Proceratium; MYRMICINAE: Acanthomyrmex, Anillomyrma, Aphaenogaster, Calyptomyrmex, Cardiocondyla, Cataulacus, Crematogaster, Dacatria, Dilobocondyla, Gauromyrmex, Kartidris, Lasiomyrma, Liomyrmex, Lophomyrmex, Lordomyrma, Mayeriella, Meranoplus, Monomorium, Myrmecina, Myrmica, Myrmicaria, Oligomyrmex, Paratopula, Parvimyrma, Pheidole, Pheidologeton, Pristomyrmex, Proatta, Pyramica, Recurvidris, Rhopalomastix, Rhoptromyrmex, Solenopsis, Strumigenys, Temnothorax, Tetramorium, Vollenhovia, Vombisidris. As the first major contribution to the third goal of the program, here we provide: (1) a key to subfamilies, (2) a key to myrmicine genera, and (3) a synopsis of myrmicine and pseudomyrmecine genera known from Vietnam. A second paper will deal with the Aenictinae, Cerapachyinae, Dorylinae, Leptanillinae Amblyoponinae, Ponerinae, Ectatomminae and Proceratiinae, and a third with the Dolichoderinae and Formicinae.

2. Computational artefacts

2016 ◽  
pp. 13-32
Author(s):  
Subrata Dasgupta
Keyword(s):  
Computer Science ◽  
Turing Machine ◽  
Abstraction Refinement ◽  
Modern Computer ◽  
Means And Ends ◽  
Rules And Principles ◽  
Human Need ◽  
Compositional Hierarchy ◽  
The Relationship

The modern computer is a hierarchically organized system of computational artefacts. Inventing, understanding, and applying rules and principles of hierarchy is a subdiscipline of computer science. ‘Computational artefacts’ explains the concepts of compositional hierarchy, the abstraction/refinement principle, and hierarchy by construction. There are three classes of computational artefacts—abstract, material, and liminal. An important example of an abstract artefact is the Turing machine. Sciences involving artefacts are sciences of the artificial, entailing the study of the relationship between means and ends. The ‘science’ in computer science is, thus, a science of means and ends. It asks: how can a computational artefact demonstrably achieve a given human need, goal, or purpose?

scholarly journals Становлення теорії синтаксичного зв’язку в українському мовознавстві (ХVІІ – початок ХХ ст.)

2018 ◽  
Vol 53 ◽  
pp. 164-184
Author(s):  
Наталя [Natalia] Віталіївна [Vitaliïvna] Кобченко [Kobchenko]
Keyword(s):  
20Th Century ◽  
Early 20Th Century ◽  
Morphological Criterion ◽  
Adequate Description ◽  
Parts Of Speech ◽  
Typical Symptom ◽  
Research Perspective ◽  
Second Stage ◽  
The Third ◽  
Third Stage

The formation of the syntactic connection theory in the Ukrainian linguistics (17th – early 20th century)In Ukrainian linguistics, there are no historiographical papers offering an adequate description of the origin and development of the syntactic connection theory. Elsewhere, I have already proposed a periodization of the research on syntactic connections from the time of the appearance of first Slavic grammars until today, which distinguishes five historical stages. The purpose of this analysis is to characterize particularly the first three periods of the development of research on syntactic connections – from the 17th century until the 1930s. The first stage (17th–18th centuries) is the beginning of the syntactic connection theory. The syntactic chapters in the grammars of this period deal with studying the ability of some parts of speech to combine with other words. The second stage (19th century) is the period of approval of terminology and formation of the ground for deepening the syntactic connection theory. All scholars of the period defined two possible realizations of the syntactic connection – agreement and government. The third stage (the beginning of the 20th century until the 1930s) was the period in which the morphological criterion prevailed. The typical symptom of this observed in the period is consideration of syntactic connections between pairs of words in isolation from the rest of the sentence components. The crucial research perspective opened up by the study is to explain in detail the development of research on syntactic connections from the 1940s until today. Tworzenie się teorii związku składniowego w językoznawstwie ukraińskim (XVII – początek XX wieku)W językoznawstwie ukraińskim brak jak dotąd historiograficznych studiów adekwatnie opisujących początki i rozwój teorii związków składniowych. W jednej z poprzednich prac zaproponowałam periodyzację badań nad związkami składniowymi od czasu ukazania się pierwszych gramatyk słowiańskich aż po dziś, wyróżniając w niej pięć etapów historycznych. Celem tej analizy jest scharakteryzowanie zwłaszcza trzech pierwszych etapów rozwoju teorii związków składniowych – od XVII wieku do lat 30. XX wieku. Pierwszy etap (XVII–XVIII wiek) wyznacza początki teorii związków składniowych. Poświęcone składni rozdziały gramatyk tego okresu badają cechy niektórych części mowy pozwalające im na łączenie się z innymi wyrazami. Drugi etap (XIX wiek) to okres uzgadniania terminologii i tworzenia podwalin pod pogłębioną teorię związków składniowych. Uczeni powszechnie wyróżniają wówczas dwa możliwe typy związków składniowych: związek zgody i rządu. Trzeci etap (od początku do lat 30. XX wieku) był okresem, w którym zapanowało kryterium morfologiczne. Typowym tego objawem, jaki można zaobserwować w tym okresie, jest rozpatrywanie związków składniowych pomiędzy parami wyrazów w oderwaniu od pozostałych części zdania. Ważną perspektywą badawczą, jaka otwiera się w rezultacie przeprowadzonych badań, jest szczegółowy opis rozwoju badań nad związkami składniowymi od lat 40. XX wieku po dzień dzisiejszy.

scholarly journals Sinoseris (Crepidinae, Cichorieae, Asteraceae), a new genus endemic to China of three species, two of them new to science

2019 ◽  
Author(s):  
Ze-Huan Wang ◽  
Norbert Kilian ◽  
Ya-Ping Chen ◽  
Hua Peng
Keyword(s):  
Phylogenetic Analysis ◽  
20Th Century ◽  
Internal Transcribed Spacer ◽  
New Genus ◽  
Field Work ◽  
Systematic Position ◽  
Early 20Th Century ◽  
The Third ◽  
Morphological Studies ◽  
Molecular Phylogenetic

AbstractElucidating the systematic position of two Chinese species described originally as Lactuca hirsuta and L. scandens, of which only historical specimens from the late 19th and early 20th century were known, field work confirmed the occurrence of three different species. Molecular phylogenetic analysis of these species based on sequences of the nuclear ribosomal internal transcribed spacer (nrITS) region uncovered a hitherto unknown lineage in a phylogenetic backbone of the subtribe Crepidinae of the sunflower family tribe Cichorieae. Substantiated by comparative morphological studies, this lineage is described as genus new to science, named Sinoseris, endemic to the Chinese provinces Sichuan and Yunnan. Two of its three species are new to science, while the third is conspecific with both L. hirsuta and L. scandens.

Patronage and Traditional Culture in the Early 20th Century

2021 ◽  
pp. 137-149
Author(s):  
Carme Oriol
Keyword(s):  
20Th Century ◽  
Traditional Culture ◽  
Early 20Th Century ◽  
Private Initiative ◽  
The Third ◽  
Award Winning

In the 1920s, the industrialist and humanist Rafael Patxot i Jubert (1872-1964) promoted and sponsored four cultural patronage projects on Catalan folklore. These were the Obra del Cançoner Popular de Catalunya, the Masia Catalana, the Llegendari Popular Català, and the Refranyer català. The aim of the projects was to collect large corpora of materials to showcase the vast wealth of traditional Catalan culture. In this chapter, the author studies the third of these projects, the Llegendari Popular Català (a collection of folk Catalan legends), by analyzing the importance of this private initiative, the competitions held to promote the collection, and the results achieved by the project. The author also evaluate the importance of one award-winning legend collection from the first competition – that presented by the modernist architect Cèsar Martinell.

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