66 research outputs found

    Factorising non-monic quadratic equations

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    In the November 2014 issue of At Right Angles, author Shashidhar Jagadeeshan, in the article “Completing the Square . . . A powerful technique, not a feared enemy!” talked about completing the square, quadratics having the shape of a parabola . . In this article, student Anushka Tonapi explains a few methods of solving non-monic quadratic equations

    [[alternative]]The Number of Steps in the Polynomial Euclidean Algorithm

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    [[abstract]]Let M be a monic polynomial over some finite fields. For polynomials a with deg a<deg M and (a,M)=1, we estimate the average value of the Euclidean Algorithm.

    On an inverse problem for a linear combination of orthogonal polynomials

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    This paper deals with the analysis of the orthogonality of a monic polynomial sequence defined as a linear combination of a sequence of monic orthogonal polynomials withwhere for . Moreover, we obtain the relation between the corresponding linear functionals as well as an explicit expression for the sequence of monic orthogonal polynomials . We obtain the connection between the Jacobi matrices associated with and , respectively, by using an LU factorization. Some special cases of the above type relation are analysed.The work of the first author (FM) has been supported by Ministerio de Economía y Competitividad of Spain, grant MTM 2012 36732 C03 01. This paper was completed during a stay of the second author (SV) in the Department of Mathematics of Universidad Carlos III de Madrid in the spring semester of the academic year 2012 2013. He acknowledges the kind reception there

    On the characterizations of third-degree semiclassical forms via polynomial mappings

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    The aim of this contribution is the study of orthogonal polynomials via polynomial mappings in the framework of the third-degree semiclassical linear forms. Let u and v be two regular forms and let denote by {pn}n≥0 and {qn}n≥0 the corresponding sequences of monic orthogonal polynomials such that there exists a monic polynomial θm of degree m, with 0 ≤ m ≤ k − 1 and r ∈ C, in such a way (...)The work of the first author (Francisco Marcellán) has been supported by [grant number PGC2018-096504-B-C31] by FEDER/ Spanish Ministry of Science and Innovation – Agencia Estatal de Investigación (AEI) of Spain

    A Personal Remembrance of Warren Bennis

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    In January 2010, I fulfilled a decades-long dream of driving Route 66 from Chicago to the Santa Monica Pier and back. On Jan. 21, 2010 I celebrated making it to the Pacific Ocean by 41 I visiting with a dear friend, the noted leadership author Warren Bennis, who lived in Santa Monic

    A note on the factorization of iterated quadratics over finite fields

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    Let ff be a monic quadratic polynomial over a finite field of odd characteristic. In 2012, Boston and Jones constructed a Markov process based on the post-critical orbit of ff, and conjectured that its limiting distribution explains the factorization of large iterates of ff. Later on, Xia, Boston, and the author did extensive Magma computations and found some exceptional families of quadratics that do not seem to follow the original Markov model conjectured by Boston and Jones. They did this by empirically observing that certain factorization patterns predicted by the Boston-Jones model never seem to occur for these polynomials, and suggested a multi-step Markov model which takes these missing factorization patterns into account. In this note, we provide proofs for all these missing factorization patterns. These are the first provable results that explain why the original conjecture of Boston and Jones does not hold for all monic quadratic polynomials.Comment: 13 page

    Continuous symmetric Sobolev inner products

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    24 pages, no figures.-- MSC2000 codes: 42C05.MR#: MR1953647 (2003j:42029)Zbl#: Zbl pre05368623In this paper we consider the sequence of monic polynomials (Qn) orthogonal with respect to a symmetric Sobolev inner product. If Q_2n(x)=Pn(x^2) and Q_2n+1(x)=xRn(x^2), then we deduce the integral representation of the inner products such that (Pn) and (Rn) are, respectively, the corresponding sequences of monic orthogonal polynomials. In the semiclassical case, algebraic relations between such sequences are deduced. Finally, an application of the above results to Freud-Sobolev polynomials is given.The work of the second author was partially supported by Dirección General de Investigación (Ministerio de Ciencia y Tecnología) of Spain under grant BFM 2000-0206-C04-01 and INTAS project INTAS 2000-272.Publicad

    Spherical Harmonic Solution of the Robin Problem for the Helmholtz Equation in a Supershaped Shell

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    The Robin problem for the Helmholtz equation in normal-polar shells is addressed by using a suitable spherical har-monic expansion technique. Attention is in particular focused on the wide class of domains whose boundaries are de-fined by a generalized version of the so-called “superformula” introduced by Gielis. A dedicated numerical procedure based on the computer algebra system Mathematica© is developed in order to validate the proposed methodology. In this way, highly accurate approximations of the solution, featuring properties similar to the classical ones, are obtainedMicroelectronicsElectrical Engineering, Mathematics and Computer Scienc

    Orthogonal polynomials for the weakly equilibrium cantor sets

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    Let K(γ) be the weakly equilibrium Cantor-type set introduced by the second author in an earlier work. It is proven that the monic orthogonal polynomials Q2 s with respect to the equilibrium measure of K(γ) coincide with the Chebyshev polynomials of the set. Procedures are suggested to find Qn of all degrees and the corresponding Jacobi parameters. It is shown that the sequence of the Widom factors is bounded below. © 2016 American Mathematical Society
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