139,718 research outputs found

    Percolation and depinning transitions in cut-and-paste models of adaptation

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    We show that a cut-and-paste model to mimic a trial-and-error process of adaptation displays two pairs of percolation and depinning transitions, one for persistence and the other for efficiency. The percolation transition signals the onset of a property and the depinning transition, the growth of the same property. Despite its simplicity, the cut-and-paste model is qualitatively the same as the Minority Game. A majority cut-and-paste model is also introduced, to mimic the spread of a trend. When both models are iterated, the majority model reaches a frozen state while the minority model converges towards an alternate state. We show that a transition from the frozen to the alternate state occurs in the limit of a non-adaptive system

    Cut and Paste

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    AbstractThe paper develops Editor, a language for manipulating semistructured documents, such as those typically available on the Web. Editor programs are based on two simple ideas, taken from text editors: “search” instructions are used to select regions of interest in a document, and “cut & paste” instructions to restructure them. We study the expressive power and the complexity of these programs. We show that they are computationally complete, in the sense that any computable document restructuring can be expressed in Editor. We also study the complexity of a safe subclass of programs, showing that it captures exactly the class of polynomial-time restructurings. The language has been implemented in Java and is currently used in the Araneus project as a basis for a wrapper-generation toolkit

    Cut-and-Paste Plagiarism: Teaching Student Researchers Boundaries

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    Librarians affiliated with educational institutions, as members of an academic community, participate in teaching students and future scholars how they share in the responsibility of upholding ethical standards of scholarship and values of academic honesty. Academic honesty, in its variant forms,was part of issues in education long before the introduction of computers. Two forms, plagiarism and copyright infringement, were chronic problems in the print realm and present additional dimensions in today’s electronic environment. The causes of copyright infringement and plagiarism are extensive and complex. Divergent positions are represented in the literature on how to deal with these issues. They are not only legal issues, but moral and ethical issues as well

    Short Proofs for Cut-and-Paste Sorting of Permutations

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    We consider the problem of determining the maximum number of moves required to sort a permutation of [n][n] using cut-and-paste operations, in which a segment is cut out and then pasted into the remaining string, possibly reversed. We give short proofs that every permutation of [n][n] can be transformed to the identity in at most \flr{2n/3} such moves and that some permutations require at least \flr{n/2} moves.Comment: 7 pages, 2 figure

    Perturbative 3-manifold invariants by cut-and-paste topology

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    We give a purely topological definition of the perturbative quantum invariants of links and 3-manifolds associated with Chern-Simons field theory. Our definition is as close as possible to one given by Kontsevich. We will also establish some basic properties of these invariants, in particular that they are universally finite type with respect to algebraically split surgery and with respect to Torelli surgery. Torelli surgery is a mutual generalization of blink surgery of Garoufalidis and Levine and clasper surgery of Habiro.Comment: 18 pages, many figures. The important change in this version is an improved blowup construction. Also 20-30 typos have been correcte
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