76 research outputs found

    Extreme values of the Riemann zeta function and its argument

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    We combine our version of the resonance method with certain convolution formulas for ζ(s)\zeta(s) and logζ(s)\log\, \zeta(s). This leads to a new Ω\Omega result for ζ(1/2+it)|\zeta(1/2+it)|: The maximum of ζ(1/2+it)|\zeta(1/2+it)| on the interval 1tT1 \le t \le T is at least exp((1+o(1))logTlogloglogT/loglogT)\exp\left((1+o(1)) \sqrt{\log T \log\log\log T/\log\log T}\right). We also obtain conditional results for S(t):=1/πS(t):=1/\pi times the argument of ζ(1/2+it)\zeta(1/2+it) and S1(t):=0tS(τ)dτS_1(t):=\int_0^t S(\tau)d\tau. On the Riemann hypothesis, the maximum of S(t)|S(t)| is at least clogTlogloglogT/loglogTc \sqrt{\log T \log\log\log T/\log\log T} and the maximum of S1(t)S_1(t) is at least c1logTlogloglogT/(loglogT)3c_1 \sqrt{\log T \log\log\log T/(\log\log T)^3} on the interval TβtTT^{\beta} \le t \le T whenever 0β<10\le \beta < 1.Comment: This is the final version of the paper which has been accepted for publication in Mathematische Annale

    New asymptotic estimates for spherical designs

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    Let N(n, t) be the minimal number of points in a spherical t-design on the unit sphere S^n in R^{n+1}. For each n >= 3, we prove a new asymptotic upper bound N(n, t) <= C(n)t^{a_n}, where C(n) is a constant depending only on n, a_3 <= 4, a_4 <= 7, a_5 <= 9, a_6 <= 11, a_7 <= 12, a_8 <= 16, a_9 <= 19, a_10 <= 22, and a_n 10.Comment: 12 page
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