Stephen Cook – författare

This book treats bounded arithmetic and propositional proof complexity from the point of view of computational complexity. The first seven chapters include the necessary logical background for the material and are suitable for a graduate course. Associated with each of many complexity classes are both a two-sorted predicate calculus theory, with induction restricted to concepts in the class, and a propositional proof system. The complexity classes range from AC0 for the weakest theory up to the polynomial hierarchy. Each bounded theorem in a theory translates into a family of (quantified) propositional tautologies with polynomial size proofs in the corresponding proof system. The theory proves the soundness of the associated proof system. The result is a uniform treatment of many systems in the literature, including Buss's theories for the polynomial hierarchy and many disparate systems for complexity classes such as AC0, AC0(m), TC0, NC1, L, NL, NC, and P.

This book treats bounded arithmetic and propositional proof complexity from the point of view of computational complexity. The first seven chapters include the necessary logical background for the material and are suitable for a graduate course. Associated with each of many complexity classes are both a two-sorted predicate calculus theory, with induction restricted to concepts in the class, and a propositional proof system. The complexity classes range from AC0 for the weakest theory up to the polynomial hierarchy. Each bounded theorem in a theory translates into a family of (quantified) propositional tautologies with polynomial size proofs in the corresponding proof system. The theory proves the soundness of the associated proof system. The result is a uniform treatment of many systems in the literature, including Buss's theories for the polynomial hierarchy and many disparate systems for complexity classes such as AC0, AC0(m), TC0, NC1, L, NL, NC, and P.

When the coronavirus pandemic took hold early in 2020, charities were among the first to respond to the resulting social and economic distress. But recent scandals and a more critical climate have overshadowed the vital role they play.What Have Charities Ever Done for Us? rebalances the debate, using case studies and interviews to illustrate how charities support people and communities, foster heritage and culture and pioneer responses to crucial social, ethical and environmental questions. It also sets the historical context, examines cases that have attracted criticisms, analyses the political response and considers how the governance, transparency and independence of charities could be improved.Charities at their best are the conscience of society and benefit most people at some point in their lives. This book brings to life the breadth and depth of their work and the contribution they make to social progress.

When the coronavirus pandemic took hold early in 2020, charities were among the first to respond to the resulting social and economic distress. But recent scandals and a more critical climate have overshadowed the vital role they play. What Have Charities Ever Done for Us? rebalances the debate, using case studies and interviews to illustrate how charities support people and communities, foster heritage and culture and pioneer responses to crucial social, ethical and environmental questions. It also sets the historical context, examines cases that have attracted criticisms, analyses the political response and considers how the governance, transparency and independence of charities could be improved. Charities at their best are the conscience of society and benefit most people at some point in their lives. This book brings to life the breadth and depth of their work and the contribution they make to social progress.

When the coronavirus pandemic took hold early in 2020, charities were among the first to respond to the resulting social and economic distress. But recent scandals and a more critical climate have overshadowed the vital role they play. What Have Charities Ever Done for Us? rebalances the debate, using case studies and interviews to illustrate how charities support people and communities, foster heritage and culture and pioneer responses to crucial social, ethical and environmental questions. It also sets the historical context, examines cases that have attracted criticisms, analyses the political response and considers how the governance, transparency and independence of charities could be improved. Charities at their best are the conscience of society and benefit most people at some point in their lives. This book brings to life the breadth and depth of their work and the contribution they make to social progress.

A gritty British police procedural with a fierce female detective at its heart, Bad Trip plunges readers into the violent world of the Essex drug gangs controlling the ecstasy trade. When a young informant is found tortured, Detective Angel Guthrie is pulled into a dark, hard-boiled hunt through Britain's criminal underworld - where every lead exposes new dangers and every secret can kill. Detective Angella “Angel” Guthrie is no stranger to danger - but this case hits harder than anything she’s faced. A young dealer, brutally tortured, mutilated, then pumped full of heroin. A terrified girlfriend who won’t speak. A coded message pointing to a possible ambush. And a violent criminal network run by Gary Hobbs, an ex-army enforcer whose reputation for brutality is legendary. With Hobbs and his henchman “Animal” running the ecstasy distribution racket like a military operation, fear keeps the streets silent… and keeps the bodies coming. As the summer heat builds, so does the pressure. Witnesses vanish. A burned corpse surfaces in a derelict WWII pillbox. A chilling threat arrives at Angel’s home. The gang grows increasingly reckless - smashing into homes, torturing suspects, and silencing anyone who even whispers the wrong name. And their attention is turning squarely towards Angel herself. Working alongside fellow officer Ted Guthrie, Angel must navigate a world of organised crime, coded pager messages, violent reprisals, and a community paralysed by fear. But with every step closer to the truth, she risks becoming the gang’s next target. And when Angel realises that Hobbs is deliberately baiting her, pushing her into the open, she must confront a terrible question:How far will she go to stop him =and what will it cost her?Dark, gripping and unflinchingly realistic, Bad Trip blends the intensity of Ian Rankin, Val McDermid, Mark Billingham, Martina Cole, and Peter James with a powerful, character-driven British noir voice all of its own. This is crime fiction that cuts deep = filled with tension, authentic police work, moral dilemmas and unforgettable moments. If you love gritty British crime thrillers, hard-boiled police procedurals, female-led detective fiction, and stories of organised crime, drugs, violence and deadly secrets, Bad Trip will keep you turning pages long into the night.

Five years on from its adoption in 1997 by the Object Management Group (OMG), the Uni?ed Modeling Language is the de facto standard for creating - agrammatic models of software systems. More than 100 books have been written about UML, and it is taught to students throughout the world. The de?nition of UML version 2 is well under way, and should be largely completed within the year. This will not only improve and enhance UML itself, including standard facilities for diagram interchange, but also make it fully integrated with other modeling technologies from the OMG, such as Meta-Object Facility (MOF) and XML Metadata Interchange (XMI). The Object Constraint Language, which has become an important vehicle for communicating detailed insights between UML researchers and practitioners, will have a much expanded speci?cation and be better integrated with the UML. The popularity of UML signi?es the possibility of a shift of immense prop- tions in the practice of software development, at least comparable to the shift from the use of assembly language to “third-generation” or “high-level” p- gramming languages. We dream of describing the behavior of software systems in terms of models, closely related to the needs of the enterprise being served, and being able to routinely translate these models automatically into executing p- grams on distributed computing systems. The OMG is promoting Model-Driven Architecture (MDA) as a signi?cant step towards this vision, and the MDA c- cept has received considerable support within the IT industry.

Five years on from its adoption in 1997 by the Object Management Group (OMG), the Uni?ed Modeling Language is the de facto standard for creating - agrammatic models of software systems. More than 100 books have been written about UML, and it is taught to students throughout the world. The de?nition of UML version 2 is well under way, and should be largely completed within the year. This will not only improve and enhance UML itself, including standard facilities for diagram interchange, but also make it fully integrated with other modeling technologies from the OMG, such as Meta-Object Facility (MOF) and XML Metadata Interchange (XMI). The Object Constraint Language, which has become an important vehicle for communicating detailed insights between UML researchers and practitioners, will have a much expanded speci?cation and be better integrated with the UML. The popularity of UML signi?es the possibility of a shift of immense prop- tions in the practice of software development, at least comparable to the shift from the use of assembly language to “third-generation” or “high-level” p- gramming languages. We dream of describing the behavior of software systems in terms of models, closely related to the needs of the enterprise being served, and being able to routinely translate these models automatically into executing p- grams on distributed computing systems. The OMG is promoting Model-Driven Architecture (MDA) as a signi?cant step towards this vision, and the MDA c- cept has received considerable support within the IT industry.