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

Majoranized Feynman rules

We point out that the compact Feynman rules for Majorana fermions proposed by Denner et al. are in fact a convention for the complex phases of (anti)spinors, valid for both Majorana and Dirac fermions. We establish the relation of this phase convention with that common in the use of spinor techniques.Comment: 5 pages, comment and reference adde

Linear quantum addition rules

The quantum integer $[n]_q$ is the polynomial $1 + q + q^2 + ... + q^{n-1}.$ Two sequences of polynomials $\mathcal{U} = \{u_n(q)\}_{n=1}^{\infty}$ and $\mathcal{V} = \{v_n(q)\}_{n=1}^{\infty}$ define a {\em linear addition rule} $\oplus$ on a sequence $\mathcal{F} = \{f_n(q)\}_{n=1}^{\infty}$ by $f_m(q)\oplus f_n(q) = u_n(q)f_m(q) + v_m(q)f_n(q).$ This is called a {\em quantum addition rule} if $[m]_q \oplus [n]_q = [m+n]_q$ for all positive integers $m$ and $n$. In this paper all linear quantum addition rules are determined, and all solutions of the corresponding functional equations $f_m(q)\oplus f_n(q) = f_{m+n}(q)$ are computed.Comment: 8 pages; to appear in Integers: The Electronic Journal of Combinatorial Number Theor