Optimal Union-Find in Constraint Handling Rules

Constraint Handling Rules (CHR) is a committed-choice rule-based language that was originally intended for writing constraint solvers. In this paper we show that it is also possible to write the classic union-find algorithm and variants in CHR. The programs neither compromise in declarativeness nor efficiency. We study the time complexity of our programs: they match the almost-linear complexity of the best known imperative implementations. This fact is illustrated with experimental results.Comment: 12 pages, 3 figures, to appear in Theory and Practice of Logic Programming (TPLP

Network Rules

Crawford compares the debate between the telcos and the online companies over broadband access regimes often called the network neutrality debate to the ongoing tussle between intellectual property maximalists and free culture advocates which are strikingly parallel sets of arguments. The maximalists claim that creativity comes from lone genuises (the romantic author) who must be given legal incentives to works but intellectual property scholars have carefully examined the incentives of their arguments and have pointed out that granting overly strong property rights to copyright holders might not be socially appropriate. Moreover, the network providers claim that they (the romantic builders) must be allowed by law to price-discriminate vis-a-vis content sources in order to be encouraged to build the network

Visiting Rules and Regulations: A Preliminary Study

A revised version of this paper was published as: Schafer, N.E. (1989). "Prison Visiting: Is It Time to Review the Rules?" Federal Probation 53(4): 25–30 (Dec 1989). (http://heinonline.org/HOL/LandingPage?collection=journals&handle=hein.journals/fedpro53&div=57&id=&page=; )Visiting rules and regulations from 71 long-term adult correctional facilities from 31 states were collected for review. The rules are divided into five areas: visitor application, visitor processing, contraband, conduct, and dress codes. They are reviewed in the light of recent standards which stress the importance of encouraging visits. Suggestions and recommendations for change are included.Abstract / [Introduction] / The Visiting Rules / Becoming a Visitor / Visitor Processing / Contraband / Conduct / Dress Codes / Reference

School rules

Gordon Murray and Alan Dunlop Architects designed an extraordinary, internationally award-winning school that started with a most challenging set of constraints. Completed in July 2007, the designers took on the project with a 'research and development' perspective that set a high bar for innovative. Designing a school for children of varying ages, needs and disabilities presented a not inconsiderable challenge as Dunlop reveals: 'We didn't have a brief we had client requirements, we had design objectives. This building has to be absolutely brilliant kind of thing.' Secured by design proved to be a heavy imposition on the architectural team, this necessitated the use of CCTV cameras and strenuous health and safety requirements

Superselection Rules

This note provides a summary of the meaning of the term `Superselection Rule' in Quantum Mechanics and Quantum-Field Theory. It is a slightly extended version of a contribution to the Compendium of Quantum Physics: Concepts, Experiments, History and Philosophy, edited by Friedel Weinert, Klaus Hentschel, Daniel Greenberger, and Brigitte Falkenburg.Comment: 10 pages, no figures. Two easy-to-read proofs of statements made in the text are added in the second version, with slight adaptations in notatio

Cosmological diagrammatic rules

A simple set of diagrammatic rules is formulated for perturbative evaluation of ``in-in" correlators, as is needed in cosmology and other nonequilibrium problems. These rules are both intuitive, and efficient for calculational purposes.Comment: 7 pages, 3 figure

Symmetric majority rules

In the standard arrovian framework and under the assumption that individual preferences and social outcomes are linear orders on the set of alternatives, we study the rules which satisfy suitable symmetries and obey the majority principle. In particular, supposing that individuals and alternatives are exogenously partitioned into subcommittees and subclasses, we provide necessary and sufficient conditions for the existence of reversal symmetric majority rules that are anonymous and neutral with respect to the considered partitions. We also determine a general method for constructing and counting those rules and we explicitly apply it to some simple cases