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The sum of multidimensional divisor function over values of quadratic polynomial

Number Theory 2017-08-15 v3

Abstract

Let F(x)=xtQmx+btx+cZ[x]F({\bf x})={\bf x}^tQ_m{\bf x}+\mathbf{b}^t{\bf x}+c\in\mathbb{Z}[{\bf x}] be a quadratic polynomial in (3)\ell (\ge 3 ) variables x=(x1,...,x){\bf x} =(x_{1},...,x_{\ell}), where F(x)F({\bf x}) is positive when xR1{\bf x}\in\mathbb{R}_{\ge 1}^{\ell}, QmM(Z)Q_m\in {\rm M}_{\ell}(\mathbb{Z}) is an ×\ell\times\ell matrix and its discriminant det(Qmt+Qm)0\det\left(Q_m^t+Q_m\right)\neq 0. It gives explicit asymptotic formulas for the following sum Tk,F(X)=x[1,X]Zτk(F(x)) T_{k,F}(X)=\sum_{{\bf x}\in [1,X]^{\ell}\cap\mathbb{Z}^{\ell}}\tau_{k}\left(F({\bf x})\right) with the help of the circle method. Here τk(n)=#{(x1,x2,...,xk)Nk:n=x1x2...xk}\tau_{k}(n)=\#\{(x_1,x_2,...,x_{k})\in\mathbb{N}^{k}: n=x_1x_2...x_{k}\} with kZ2k\in\mathbb{Z}_{\ge 2} is the multidimensional divisor function.

Keywords

Cite

@article{arxiv.1703.10546,
  title  = {The sum of multidimensional divisor function over values of quadratic polynomial},
  author = {Nianhong Zhou},
  journal= {arXiv preprint arXiv:1703.10546},
  year   = {2017}
}

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16 pages