206 research outputs found

    Note on the nonvanishing of L(1)

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    Prediction of Adolescent Sexual Reoffending: A Meta-Analysis of the J-SOAP-II, ERASOR, J-SORRAT-II, and Static-99

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    Several risk assessment tools, including the Juvenile Sex Offender Assessment Protocol-II (Prentky & Righthand, 2003), the Estimate of Risk of Adolescent Sexual Offense Recidivism (Worling & Curwen, 2001), the Juvenile Sexual Offense Recidivism Risk Assessment Tool-II (Epperson, ralston, Fowers, DeWitt, & Gore, 2006), and the Static-99 (Hanson & Thornton, 1999), have been used to assess reoffense risk among adolescents who have committed sexual offenses. Given that research on these tools has yielded somewhat mixed results, we empirically synthesized 33 published and unpublished studies involving 6,196 male adolescents who had committed a sexual offense. We conducted two separate meta-analyses, first with correlations and then with AUCs. Total scores on each of the tools significantly predicted sexual reoffending, with aggregated correlations ranging from .12 - .20 and aggregated area under the receiver operating characteristic curve (AUC) scores ranging from .64 - .67. In many cases, however, heterogeneity across studies was moderate to high. There were no significant differences between tools, and although the Static-99 was developed for adults, it achieved similar results as the adolescent tools. To help interpret these findings, results are compared to other meta-analyses of risk tools used in the area of violence risk assessment and in other fields

    Constructions of diagonal quartic and sextic surfaces with infinitely many rational points

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    In this note we construct several infinite families of diagonal quartic surfaces \begin{equation*} ax^4+by^4+cz^4+dw^4=0, \end{equation*} where a,b,c,d∈Z∖{0}a,b,c,d\in\Z\setminus\{0\} with infinitely many rational points and satisfying the condition abcd≠□abcd\neq \square. In particular, we present an infinite family of diagonal quartic surfaces defined over \Q with Picard number equal to one and possessing infinitely many rational points. Further, we present some sextic surfaces of type ax6+by6+cz6+dwi=0ax^6+by^6+cz^6+dw^i=0, i=2i=2, 33, or 66, with infinitely many rational points.Comment: revised version will appear in International Journal of Number Theor

    On the Quantum Invariant for the Brieskorn Homology Spheres

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    We study an exact asymptotic behavior of the Witten-Reshetikhin-Turaev invariant for the Brieskorn homology spheres Σ(p1,p2,p3)\Sigma(p_1,p_2,p_3) by use of properties of the modular form following a method proposed by Lawrence and Zagier. Key observation is that the invariant coincides with a limiting value of the Eichler integral of the modular form with weight 3/2. We show that the Casson invariant is related to the number of the Eichler integrals which do not vanish in a limit τ→N∈Z\tau\to N \in \mathbb{Z}. Correspondingly there is a one-to-one correspondence between the non-vanishing Eichler integrals and the irreducible representation of the fundamental group, and the Chern-Simons invariant is given from the Eichler integral in this limit. It is also shown that the Ohtsuki invariant follows from a nearly modular property of the Eichler integral, and we give an explicit form in terms of the L-function.Comment: 26 pages, 2 figure

    Louis Joel Mordell's time in London

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    The celebrated number theorist Louis Joel Mordell spent around two and a half decades working in Manchester and for most of the rest of his career he was based in St John’s College, Cambridge. There was, however, a brief period when he was based in London. The standard biographies of Mordell’s life by and largely tend to overlook this period almost to the point of being deceptive about it. In this paper we will address this imbalance by discussing this chapter in Mordell’s life in more detail

    Quantum Invariants, Modular Forms, and Lattice Points II

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    We study the SU(2) Witten--Reshetikhin--Turaev invariant for the Seifert fibered homology spheres with M-exceptional fibers. We show that the WRT invariant can be written in terms of (differential of) the Eichler integrals of modular forms with weight 1/2 and 3/2. By use of nearly modular property of the Eichler integrals we shall obtain asymptotic expansions of the WRT invariant in the large-N limit. We further reveal that the number of the gauge equivalent classes of flat connections, which dominate the asymptotics of the WRT invariant in N ->\infinity, is related to the number of integral lattice points inside the M-dimensional tetrahedron

    K-Rational D-Brane Crystals

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    In this paper the problem of constructing spacetime from string theory is addressed in the context of D-brane physics. It is suggested that the knowledge of discrete configurations of D-branes is sufficient to reconstruct the motivic building blocks of certain Calabi-Yau varieties. The collections of D-branes involved have algebraic base points, leading to the notion of K-arithmetic D-crystals for algebraic number fields K. This idea can be tested for D0-branes in the framework of toroidal compactifications via the conjectures of Birch and Swinnerton-Dyer. For the special class of D0-crystals of Heegner type these conjectures can be interpreted as formulae that relate the canonical Neron-Tate height of the base points of the D-crystals to special values of the motivic L-function at the central point. In simple cases the knowledge of the D-crystals of Heegner type suffices to uniquely determine the geometry.Comment: 36 page

    Quantum Fourier transform, Heisenberg groups and quasiprobability distributions

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    This paper aims to explore the inherent connection among Heisenberg groups, quantum Fourier transform and (quasiprobability) distribution functions. Distribution functions for continuous and finite quantum systems are examined first as a semiclassical approach to quantum probability distribution. This leads to studying certain functionals of a pair of "conjugate" observables, connected via the quantum Fourier transform. The Heisenberg groups emerge naturally from this study and we take a rapid look at their representations. The quantum Fourier transform appears as the intertwining operator of two equivalent representation arising out of an automorphism of the group. Distribution functions correspond to certain distinguished sets in the group algebra. The marginal properties of a particular class of distribution functions (Wigner distributions) arise from a class of automorphisms of the group algebra of the Heisenberg group. We then study the reconstruction of Wigner function from the marginal distributions via inverse Radon transform giving explicit formulas. We consider applications of our approach to quantum information processing and quantum process tomography.Comment: 39 page

    On two-dimensional Bessel functions

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    The general properties of two-dimensional generalized Bessel functions are discussed. Various asymptotic approximations are derived and applied to analyze the basic structure of the two-dimensional Bessel functions as well as their nodal lines.Comment: 25 pages, 17 figure

    On Witten multiple zeta-functions associated with semisimple Lie algebras IV

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    In our previous work, we established the theory of multi-variable Witten zeta-functions, which are called the zeta-functions of root systems. We have already considered the cases of types A2A_2, A3A_3, B2B_2, B3B_3 and C3C_3. In this paper, we consider the case of G2G_2-type. We define certain analogues of Bernoulli polynomials of G2G_2-type and study the generating functions of them to determine the coefficients of Witten's volume formulas of G2G_2-type. Next we consider the meromorphic continuation of the zeta-function of G2G_2-type and determine its possible singularities. Finally, by using our previous method, we give explicit functional relations for them which include Witten's volume formulas.Comment: 22 pag
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