1,238 research outputs found

    Overinterpolation

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    In this paper we study the consequences of overinterpolation, i.e., the situation when a function can be interpolated by polynomial, or rational, or algebraic functions in more points that normally expected. We show that in many cases such a function has specific forms.Comment: 14 page

    Stable algebras of entire functions

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    Suppose that hh and gg belong to the algebra \B generated by the rational functions and an entire function ff of finite order on Cn{\Bbb C}^n and that h/gh/g has algebraic polar variety. We show that either h/g\in\B or f=q1ep+q2f=q_1e^p+q_2, where pp is a polynomial and q1,q2q_1,q_2 are rational functions. In the latter case, h/gh/g belongs to the algebra generated by the rational functions, epe^p and epe^{-p}.Comment: 11 page

    Polynomial estimates, exponential curves and Diophantine approximation

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    Let α(0,1)Q\alpha\in(0,1)\setminus{\Bbb Q} and K={(ez,eαz):z1}C2K=\{(e^z,e^{\alpha z}):\,|z|\leq1\}\subset{\Bbb C}^2. If PP is a polynomial of degree nn in C2{\Bbb C}^2, normalized by PK=1\|P\|_K=1, we obtain sharp estimates for PΔ2\|P\|_{\Delta^2} in terms of nn, where Δ2\Delta^2 is the closed unit bidisk. For most α\alpha, we show that supPPΔ2exp(Cn2logn)\sup_P\|P\|_{\Delta^2}\leq\exp(Cn^2\log n). However, for α\alpha in a subset S{\mathcal S} of the Liouville numbers, supPPΔ2\sup_P\|P\|_{\Delta^2} has bigger order of growth. We give a precise characterization of the set S{\mathcal S} and study its properties.Comment: 12 pages. To appear in Mathematical Research Letter

    Transcendence measures and algebraic growth of entire functions

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    In this paper we obtain estimates for certain transcendence measures of an entire function ff. Using these estimates, we prove Bernstein, doubling and Markov inequalities for a polynomial P(z,w)P(z,w) in C2{\Bbb C}^2 along the graph of ff. These inequalities provide, in turn, estimates for the number of zeros of the function P(z,f(z))P(z,f(z)) in the disk of radius rr, in terms of the degree of PP and of rr. Our estimates hold for arbitrary entire functions ff of finite order, and for a subsequence {nj}\{n_j\} of degrees of polynomials. But for special classes of functions, including the Riemann ζ\zeta-function, they hold for all degrees and are asymptotically best possible. From this theory we derive lower estimates for a certain algebraic measure of a set of values f(E)f(E), in terms of the size of the set EE.Comment: 40 page

    Pade interpolation by F-polynomials and transfinite diameter

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    We define FF-polynomials as linear combinations of dilations by some frequencies of an entire function FF. In this paper we use Pade interpolation of holomorphic functions in the unit disk by FF-polynomials to obtain explicitly approximating FF-polynomials with sharp estimates on their coefficients. We show that when frequencies lie in a compact set KCK\subset\mathbb C then optimal choices for the frequencies of interpolating polynomials are similar to Fekete points. Moreover, the minimal norms of the interpolating operators form a sequence whose rate of growth is determined by the transfinite diameter of KK. In case of the Laplace transforms of measures on KK, we show that the coefficients of interpolating polynomials stay bounded provided that the frequencies are Fekete points. Finally, we give a sufficient condition for measures on the unit circle which ensures that the sums of the absolute values of the coefficients of interpolating polynomials stay bounded.Comment: 16 page

    Religion, popular culture and social media: the construction of a religious leader image on Facebook

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    Despite the emergence of religions on Internet and the importance of social media, research dedicated to religious leaders’ construction of symbolic image on social media, is hard to find. Starting from the 2013 Applebee’s social media crisis, which was triggered by a pastor, the present study investigates the frames and themes Facebook users employed in order to give meaning to the crisis, attribute responsibility, and more importantly, define the role of a religious leader in daily life. This study shows the existence on social media of an active religious literate public, a public clearly troubled in their religious faith and convictions by the non-Christian behavior of the pastor. This shows that in a post-secular society the religious imaginary is not only a “canopy” inherited and kept because of convenience, but a cultural frame of signification the real and a vector of dialogue in a (online) micro and macro public sphere

    Smooth submanifolds intersecting any analytic curve in a discrete set

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    We construct examples of CC^\infty smooth submanifolds in Cn{\Bbb C}^n and Rn{\Bbb R}^n of codimension 2 and 1, which intersect every complex, respectively real, analytic curve in a discrete set. The examples are realized either as compact tori or as properly imbedded Euclidean spaces, and are the graphs of quasianalytic functions. In the complex case, these submanifolds contain real nn-dimensional tori or Euclidean spaces that are not pluripolar while the intersection with any complex analytic disk is polar

    Quasianalyticity and pluripolarity

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    We show that the graph Γf={(z,f(z))C2:zS}\Gamma_f=\{(z,f(z))\in{\Bbb C}^2: z\in S\} in C2{\Bbb C}^2 of a function ff on the unit circle SS which is either continuous and quasianalytic in the sense of Bernstein or CC^\infty and quasianalytic in the sense of Denjoy is pluripolar
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