Emphasizes the computer science aspects of the subject. Details applications in databases, complexity theory, and formal languages, as well as other branches of computer science.
Finite model theory,as understoodhere, is an areaof mathematicallogic that has developed in close connection with applications to computer science, in particular the theory of computational complexity and database theory. One of the fundamental insights of mathematical logic is that our understanding of mathematical phenomena is enriched by elevating the languages we use to describe mathematical structures to objects of explicit study. If mathematics is the science of patterns, then the media through which we discern patterns, as well as the structures in which we discern them, command our attention. It isthis aspect oflogicwhichis mostprominentin model theory,“thebranchof mathematical logic which deals with the relation between a formal language and its interpretations”. No wonder, then, that mathematical logic, and ?nite model theory in particular, should ?nd manifold applications in computer science: from specifying programs to querying databases, computer science is rife with phenomena whose understanding requires close attention to the interaction between language and structure. This volume gives a broadoverviewof some central themes of ?nite model theory: expressive power, descriptive complexity, and zero–one laws, together with selected applications to database theory and arti?cial intelligence, es- cially constraint databases and constraint satisfaction problems. The ?nal chapter provides a concise modern introduction to modal logic,which emp- sizes the continuity in spirit and technique with ?nite model theory.
This is the first comprehensive survey of the field of constraint databases, written by leading researchers. Constraint databases are a fairly new and active area of database research. Their ability to deal with infinite sets makes them particularly promising as a technology for integrating spatial and temporal data with standard relational databases. Constraint databases bring techniques from a variety of fields, such as logic and model theory, algebraic and computational geometry, as well as symbolic computation, to the design and analysis of data models and query languages.
Data exchange is the problem of finding an instance of a target schema, given an instance of a source schema and a specification of the relationship between the source and the target. Such a target instance should correctly represent information from the source instance under the constraints imposed by the target schema, and it should allow one to evaluate queries on the target instance in a way that is semantically consistent with the source data. Data exchange is an old problem that re-emerged as an active research topic recently, due to the increased need for exchange of data in various formats, often in e-business applications. In this lecture, we give an overview of the basic concepts of data exchange in both relational and XML contexts. We give examples of data exchange problems, and we introduce the main tasks that need to addressed. We then discuss relational data exchange, concentrating on issues such as relational schema mappings, materializing target instances (including canonical solutions and cores), query answering, and query rewriting. After that, we discuss metadata management, i.e., handling schema mappings themselves. We pay particular attention to operations on schema mappings, such as composition and inverse. Finally, we describe both data exchange and metadata management in the context of XML. We use mappings based on transforming tree patterns, and we show that they lead to a host of new problems that did not arise in the relational case, but they need to be addressed for XML. These include consistency issues for mappings and schemas, as well as imposing tighter restrictions on mappings and queries to achieve tractable query answering in data exchange. Table of Contents: Overview / Relational Mappings and Data Exchange / Metadata Management / XML Mappings and Data Exchange
This is the first comprehensive survey of the field of constraint databases, written by leading researchers. Constraint databases are a fairly new and active area of database research. Their ability to deal with infinite sets makes them particularly promising as a technology for integrating spatial and temporal data with standard relational databases. Constraint databases bring techniques from a variety of fields, such as logic and model theory, algebraic and computational geometry, as well as symbolic computation, to the design and analysis of data models and query languages.
Finite model theory,as understoodhere, is an areaof mathematicallogic that has developed in close connection with applications to computer science, in particular the theory of computational complexity and database theory. One of the fundamental insights of mathematical logic is that our understanding of mathematical phenomena is enriched by elevating the languages we use to describe mathematical structures to objects of explicit study. If mathematics is the science of patterns, then the media through which we discern patterns, as well as the structures in which we discern them, command our attention. It isthis aspect oflogicwhichis mostprominentin model theory,“thebranchof mathematical logic which deals with the relation between a formal language and its interpretations”. No wonder, then, that mathematical logic, and ?nite model theory in particular, should ?nd manifold applications in computer science: from specifying programs to querying databases, computer science is rife with phenomena whose understanding requires close attention to the interaction between language and structure. This volume gives a broadoverviewof some central themes of ?nite model theory: expressive power, descriptive complexity, and zero–one laws, together with selected applications to database theory and arti?cial intelligence, es- cially constraint databases and constraint satisfaction problems. The ?nal chapter provides a concise modern introduction to modal logic,which emp- sizes the continuity in spirit and technique with ?nite model theory.
Data exchange is the problem of finding an instance of a target schema, given an instance of a source schema and a specification of the relationship between the source and the target. Such a target instance should correctly represent information from the source instance under the constraints imposed by the target schema, and it should allow one to evaluate queries on the target instance in a way that is semantically consistent with the source data. Data exchange is an old problem that re-emerged as an active research topic recently, due to the increased need for exchange of data in various formats, often in e-business applications. In this lecture, we give an overview of the basic concepts of data exchange in both relational and XML contexts. We give examples of data exchange problems, and we introduce the main tasks that need to addressed. We then discuss relational data exchange, concentrating on issues such as relational schema mappings, materializing target instances (including canonical solutions and cores), query answering, and query rewriting. After that, we discuss metadata management, i.e., handling schema mappings themselves. We pay particular attention to operations on schema mappings, such as composition and inverse. Finally, we describe both data exchange and metadata management in the context of XML. We use mappings based on transforming tree patterns, and we show that they lead to a host of new problems that did not arise in the relational case, but they need to be addressed for XML. These include consistency issues for mappings and schemas, as well as imposing tighter restrictions on mappings and queries to achieve tractable query answering in data exchange. Table of Contents: Overview / Relational Mappings and Data Exchange / Metadata Management / XML Mappings and Data Exchange
Emphasizes the computer science aspects of the subject. Details applications in databases, complexity theory, and formal languages, as well as other branches of computer science.
Lonely Planet: The world’s number one travel guide publisher* Lonely Planet’s Ukraine is your passport to the most relevant, up-to-date advice on what to see and skip, and what hidden discoveries await you. Sip morning coffee in Lviv’s cosy cafes, hike the flower-filled upland pastures and wide, snaking valleys of the Carpathian Mountains, and take a guided tour of Chernobyl – all with your trusted travel companion. Get to the heart of Ukraine and begin your journey now! Inside Lonely Planet’s Ukraine: Colour maps and images throughout Highlights and itineraries help you tailor your trip to your personal needs and interests Insider tips to save time and money and get around like a local, avoiding crowds and trouble spots Essential info at your fingertips - hours of operation, phone numbers, websites, transit tips, prices Honest reviews for all budgets - eating, sleeping, sightseeing, going out, shopping, hidden gems that most guidebooks miss Cultural insights provide a richer, more rewarding travel experience - covering history, people, music, arts, landscapes, wildlife, cuisine, politics Covers Kyiv, Central Ukraine, Lviv & Western Ukraine, The Carpathians, Southern Ukraine, Crimea, Eastern Ukraine eBook Features: (Best viewed on tablet devices and smartphones) Downloadable PDF and offline maps prevent roaming and data charges Effortlessly navigate and jump between maps and reviews Add notes to personalise your guidebook experience Seamlessly flip between pages Bookmarks and speedy search capabilities get you to key pages in a flash Embedded links to recommendations' websites Zoom-in maps and images Inbuilt dictionary for quick referencing The Perfect Choice: Lonely Planet’s Ukraine is our most comprehensive guide to Ukraine, and is designed to immerse you in the culture and help you discover the best sights and get off the beaten track. About Lonely Planet: Lonely Planet is a leading travel media company and the world’s number one travel guidebook brand, providing both inspiring and trustworthy information for every kind of traveller since 1973. Over the past four decades, we’ve printed over 145 million guidebooks and grown a dedicated, passionate global community of travellers. You’ll also find our content online, and in mobile apps, video, 14 languages, nine international magazines, armchair and lifestyle books, ebooks, and more. ‘Lonely Planet guides are, quite simply, like no other.’ – New York Times ‘Lonely Planet. It's on everyone's bookshelves; it's in every traveller's hands. It's on mobile phones. It's on the Internet. It's everywhere, and it's telling entire generations of people how to travel the world.’ – Fairfax Media (Australia) *Source: Nielsen BookScan: Australia, UK, USA, 5/2016-4/2017 Important Notice: The digital edition of this book may not contain all of the images found in the physical edition.
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