On the mean square of the error term for the two-dimensional divisor problem (I)

Mean square of the error term in the asymmetric many dimensional divisor problem

Let $\ba=(a_1,a_2,\ldots,a_k)$, where $a_j \ (j=1,\ldots,k)$ are positive integers such that $a_1 \leq a_2 \leq \cdots \leq a_k$. Let $d(\ba;n)=\sum_{n_1^{a_1}\cdots n_k^{a_k}=n}1$ and $Δ(\ba;x)$ be the error term of the summatory function of $d(\ba;n)$. In this paper we show an asymptotic formula of the mean square of $Δ(\ba;x)$ under a certain condition. Furthermore, in the cases $k=2$ and 3, we give unconditional asymptotic formulas for these mean squares.

Uniform Titchmarsh divisor problems

Asymptotic formulae for Titchmarsh-type divisor sums are obtained with strong error terms that are uniform in the shift parameter. This applies to more general arithmetic functions such as sums of two squares, improving the error term in the representation of the number as a sum of a prime and two squares, and to Fourier coefficients of cusp forms, generalizing a result of Pitt.

关于与完美平方整数相关的除数函数的渐进行为

On the Asymptotic Behavior of a Multiplicative Arithmetic Function Related to the Divisor Function Over Perfect Squares Integers Generated by Shifting

本文研究了与完美平方整数相关的除数函数的渐进行为，推导了特定求和式的渐近公式。

平移素数的最大的平方因子

Largest square divisors of shifted primes

该论文证明存在无穷多个素数 $p$，使得对任意非零整数 $a$，$p-a$ 有大于 $p^{1/2+1/700}$ 的平方因子，改进了 Merikoski 的指数，并使用了 Harman 筛法中的强力工具。

Modular units and cuspidal divisor classes on $X_0(n^2M)$ with $n|24$ and $M$ squarefree

For a positive integer $N$, let $\mathscr C(N)$ be the subgroup of $J_0(N)$ generated by the equivalence classes of cuspidal divisors of degree $0$ and $\mathscr C(N)(\mathbb Q):=\mathscr C(N)\cap J_0(N)(\mathbb Q)$ be its $\mathbb Q$-rational subgroup. Let also $\mathscr C_{\mathbb Q}(N)$ be the subgroup of $\mathscr C(N)(\mathbb Q)$ generated by $\mathbb Q$-rational cuspidal divisors. We prove that when $N=n^2M$ for some integer $n$ dividing $24$ and some squarefree integer $M$, the two groups $\mathscr C(N)(\mathbb Q)$ and $\mathscr C_{\mathbb Q}(N)$ are equal. To achieve this, we show that…

On the integral of the error term in the Dirichlet divisor problem

Several results are obtained concerning the function $Δ_k(x)$, which represents the error term in the general Dirichlet divisor problem. These include the estimates for the integral of this function, as well as for the corresponding mean square integral. The mean square integral of $Δ_2(x)$ is investigated in detail.

The Mean Square of Divisor Function

Let $d(n)$ be the divisor function. In 1916, S. Ramanujan stated but without proof that $$\sum_{n\leq x}d^2(n)=xP(\log x)+E(x), $$ where $P(y)$ is a cubic polynomial in $y$ and $$ E(x)=O(x^{{3\over 5}+ε}), $$ where $ε$ is a sufficiently small positive constant. He also stated that, assuming the Riemann Hypothesis(RH), $$ E(x)=O(x^{{1\over 2}+ε}). $$ In 1922, B. M. Wilson proved the above result unconditionally. The direct application of the RH would produce $$ E(x)=O(x^{1\over 2}(\log x)^5\log\log x). $$ In 2003, K. Ramachandra and A. Sankaranarayanan proved the above result without any assump…

具有Hecke特征值平方权重和Piltz除数函数权重的遍历平均

Ergodic averages with the Hecke eigenvalue square weights and the Piltz divisor function weights

本文证明Hecke特征值平方与Piltz除数函数可作为逐点遍历定理的良好权重，部分解决Cuny和Weber的问题，并推广至其他算术函数。

On the largest square divisor of shifted primes

We show that there are infinitely many primes $p$ such that $p-1$ is divisible by a square $d^2 \geq p^θ$ for $θ=1/2+1/2000.$ This improves the work of Matomäki (2009) who obtained the result for $θ=1/2-\varepsilon$ (with the added constraint that $d$ is also a prime), which improved the result of Baier and Zhao (2006) with $θ=4/9-\varepsilon.$ Similarly as in the work of Matomäki, we apply Harman's sieve method to detect primes $p \equiv 1 \, (d^2)$. To break the $θ=1/2$ barrier we prove a new bilinear equidistribution estimate modulo smooth square moduli $d^2$ by using a similar argument as …

A Weighted Divisor Problem

We study a weighted divisor function $\mathop{{\sum}'}\limits_{mn\leq x}\cos(2πmθ_1)\sin(2πnθ_2)$, where $θ_i (0<θ_i<1)$ is a rational number. By connecting it with the divisor problem with congruence conditions, we establish the upper bound, mean-value, mean-square and some power-moments.

Every integer can be written as a square plus a squarefree

In the paper we can prove that every integer can be written as the sum of two integers, one perfect square and one squarefree. We also establish the asympotic formula for the number of representations of an integer in this form. The result is deeply related with the divisor function. In the course of our study we get an independent result about it. Concretely we are able to deduce a new upper bound for the divisor function valid for any integer and fully explicit.

On sums of the small divisors of a natural number

We consider the positive divisors of a natural number that do not exceed its square root, to which we refer as the {\it small divisors\/} of the natural number. We determine the asymptotic behavior of the arithmetic function that adds the small divisors of a natural number, and we consider its Dirichlet generating series.

Divisor Problem and an Analogue of Euler's Summation Formula

By simple elementary method,we obtain with ease,a highly simple expression for the remainder term of the divisor problem and use it to obtain an Euler-Maclaurin analogue of summation involving divisor function.We also obtain a relation connecting the remainder term of the divisor problem and the remainders of approximate functional equations for Riemann zeta function and its square,for positive values of arguments.

关于素数上Dirichlet除数函数误差项之和的研究

On a sum of the error term of the Dirichlet divisor function over primes

本文研究素数上Dirichlet除数函数误差项平方的求和问题，并证明了该和式存在渐近公式。

A Generalization of Lehman's Method

A new deterministic algorithm for finding square divisors, and finding $r$-power divisors in general, is presented. This algorithm is based on Lehman's method for integer factorization and is straightforward to implement. While the theoretical complexity of the new algorithm is far from best known, the algorithm becomes especially effective if even a loose bound on a square divisor is known. Additionally, we answer a question by D. Harvey and M. Hittmeir on whether their recent deterministic algorithm for integer factorization can be adapted to finding $r$-power divisors.

On generalized modular forms with a cuspidal divisor

In [6], Kohnen proves that if $Γ=Γ_0(N)$ where $N$ is a square-free integer, then any modular function of weight $0$ for $Γ$ having a divisor supported at the cusps is an $η$-product. Under the condition of having rational Fourier coefficients, we are able to extend Kohnen's result to the case where $N$ is the square of a prime. If the rationality condition does not hold, we show that the statement is no longer true by providing a family of counter-examples that generalizes naturally the Dedekind $η$-function. This paper fits within the framework of generalized modular forms in the sense of Kn…

On primitive divisors of n^2+b

We study primitive divisors of terms of the sequence P_n=n^2+b, for a fixed integer b which is not a negative square. It seems likely that the number of terms with a primitive divisor has a natural density. This seems to be a difficult problem. We survey some results about divisors of this sequence as well as provide upper and lower growth estimates for the number of terms which have a primitive divisor.

On triple correlations of divisor functions

We prove an asymptotic formula with power saving error term for a certain triple divisor sum.

On the higher moments of the error term in the divisor problem

Let $Δ(x)$ denote the error term in the Dirichlet divisor problem. Our main results are the asymptotic formulas $$ \int_1^X Δ^3(x){\rm d}x = BX^{7/4} + O_ε(X^{β+ε}) \qquad(B > 0) $$ and $$ \int_1^X Δ^4(x){\rm d}x = CX^2 + O_ε(X^{γ+ε}) \qquad(C > 0) $$ with $β= 7/5, γ= 23/12$. This improves on the values $β= 47/28, γ= 45/23$, due to K.-M. Tsang. A result on the integrals of $Δ^3(x)$ and $Δ^4(x)$ in short intervals is also proved.

Higher moments of the error term in the divisor problem

It is proved that, if $k\ge2$ is a fixed integer and $1 \ll H \le X/2$, then $$ \int_{X-H}^{X+H}Δ^4_k(x)\d x \ll_εX^ε\Bigl(HX^{(2k-2)/k} + H^{(2k-3)/(2k+1)}X^{(8k-8)/(2k+1)}\Bigr), $$ where $Δ_k(x)$ is the error term in the general Dirichlet divisor problem. The proof uses the Vorono{\"ı}--type formula for $Δ_k(x)$, and the bound of Robert--Sargos for the number of integers when the difference of four $k$--th roots is small. We also investigate the size of the error term in the asymptotic formula for the $m$-th moment of $Δ_2(x)$.

On the Riemann zeta-function and the divisor problem

Let $Δ(x)$ denote the error term in the Dirichlet divisor problem, and $E(T)$ the error term in the asymptotic formula for the mean square of $|ζ(1/2 + it)|$. If $E^*(t) = E(t) - 2πΔ^*(t/(2π))$ with $Δ^*(x) = - Δ(x) +2Δ(2x)- {1\over2}Δ(4x)$, then we obtain $$ \int_0^T(E^*(t))^4 dt \ll_εT^{16/19+varepsilon}$$, which is the first non-trivial bound for higher moments of $E^*(t)$. The method of proof also provides an upper bound for sums of fourth powers of mean square integrals of $|ζ(1/2 + it)|$ over well-spaced points. This, in turn, yields a new proof of the twelfth moment estimate for $|ζ(1/2…

Sums of divisor functions in $F_{q}[t]$ and matrix integrals

We study the mean square of sums of the $k$th divisor function $d_k(n)$ over short intervals and arithmetic progressions for the rational function field over a finite field of $q$ elements. In the limit as $q\rightarrow\infty$ we establish a relationship with a matrix integral over the unitary group. Evaluating this integral enables us to compute the mean square of the sums of $d_k(n)$ in terms of a lattice point count. This lattice point count can in turn be calculated in terms of certain polynomials, which we analyse. Our results suggest general conjectures for the corresponding classical pr…

关于广义除数问题误差项的显式和有效估计

Explicit and Effective Estimates for the error term in the Generalised Divisor Problem

本文对广义除数问题中误差项Δ_k(x)的误差项进行了显式和有效估计，特别是k在3到9之间的整数，改进了已知显式界限中的x幂次，并提供了推导所有k≥3整数误差项界限的方法。

利用共振法得到的除数问题与圆问题的Ω结果

Omega Results for The Divisor and Circle Problems Using The Resonance Method

该研究将共振法用于获取带正系数的一般指数和的大值，改进了数论中多个经典问题的Ω界，包括除数问题、圆问题及zeta函数和L函数的均方误差问题。

On the average number of divisors of reducible quadratic polynomials

We give an asymptotic formula for the divisor sum $\sum_{c<n\leq N}τ\left((n-b)(n-c)\right)$ for integers $b<c$ of the same parity. Interestingly, the coefficient of the main term does not depend on the discriminant as long as it is a full square. We also provide effective upper bounds of the average divisor sum for some of the reducible quadratic polynomials considered before, with the same main term as in the asymptotic formula.

关于带同余条件的非对称二维除数问题误差项均方值

On the mean square of the error term for the asymmetric two-dimensional divisor problem with congruence conditions

本文研究带同余条件的非对称二维除数函数，建立了其和式误差项均方值的渐近公式，改进了Zhai和Cao的已有结果。

On the divisor function and the Riemann zeta-function in short intervals

We obtain, for $T^ε\le U=U(T)\le T^{1/2-ε}$, asymptotic formulas for $$ \int_T^{2T}(E(t+U) - E(t))^2 dt,\quad \int_T^{2T}(Δ(t+U) - Δ(t))^2 dt, $$ where $Δ(x)$ is the error term in the classical divisor problem, and $E(T)$ is the error term in the mean square formula for $|ζ(1/2+it)|$. Upper bounds of the form $O_ε(T^{1+ε}U^2)$ for the above integrals with biquadrates instead of square are shown to hold for $T^{3/8} \le U =U(T) \ll T^{1/2}$. The connection between the moments of $E(t+U) - E(t)$ and $|ζ(1/2+it)|$ is also given. Generalizations to some other number-theoretic error terms are discu…

On certain integrals involving the Dirichlet divisor problem

We prove that $$ \int_1^XΔ(x)Δ_3(x)\,dx \ll X^{13/9}\log^{10/3}X, \quad \int_1^XΔ(x)Δ_4(x)\,dx \ll_\varepsilon X^{25/16+\varepsilon}, $$ where $Δ_k(x)$ is the error term in the asymptotic formula for the summatory function of $d_k(n)$, generated by $ζ^k(s)$ ($Δ_2(x) \equiv Δ(x)$). These bounds are sharper than the ones which follow by the Cauchy-Schwarz inequality and mean square results for $Δ_k(x)$. We also obtain the analogues of the above bounds when $\D(x)$ is replaced by $E(x)$, the error term in the mean square formula for $|ζ(1/2+it)|$.

Piltz divisor problem over number fields à la Voronoï

In this article, we study the Piltz divisor problem, which is sometimes called the generalized Dirichlet divisor problem, over number fields. We establish an identity akin to Voronoï's formula concerning the error term in the Dirichlet divisor problem.

关于素数上 Dirichlet 除数函数误差项的高次幂矩

On high power moments of the error term of the Dirichlet divisor function over primes

本文研究素数上 Dirichlet 除数函数求和误差项 $Δ(p)$ 在 $3\leqslant k\leqslant9$ 时的高次幂矩，并建立其渐近公式。

On an approximate functional equation involving the divisor function

The error term in the approximate functional equation for exponential sums involving the divisor function will be improved under certain conditions for the parameters of the approximate functional equation.

Subconvexity for the Riemann zeta-function and the divisor problem

A simple proof of the classical subconvexity bound $ζ(1/2+it) \ll_εt^{1/6+ε}$ for the Riemann zeta-function is given, and estimation by more refined techniques is discussed. The connections between the Dirichlet divisor problem and the mean square of $|ζ(1/2+it)|$ are analysed.

一个加权除数问题与指数和

A weighted divisor problem and exponential sum

本文针对 $ζ'(s)^2$ 的 Dirichlet 级数系数 $D_{(1)}(n)$ 的加权指数和，建立截断 Voronoï 型公式，并由此得到误差项的均方估计，同时研究了相应 Riesz 和及其误差项的均方估计。

Fixed points of the sum of divisors function on $F_2[x]$

We work an analogue of a classical arithmetic problem over polynomials. More precisely, we study the fixed points $F$ of the sum of divisors function $σ: F_2[x] \mapsto F_2[x]$ (defined \emph{mutatis mutandi} like the usual sum of divisors over the integers) of the form $F := A^2 \cdot S$, $S$ square-free, with $ω(S) \leq 3$, coprime with $A$, for $A$ even, of whatever degree, under some conditions. This gives a characterization of $5$ of the $11$ known fixed points of $σ$ in $F_2[x]$

Omega results for the divisor and circle problems

We obtain new omega results for the error terms in two classical lattice point problems. These results are likely to be the best possible.

临界带中黎曼zeta函数与Dirichlet多项式乘积的均方值

The mean square of the product of the Riemann zeta-function and a Dirichlet polynomial in the critical strip

本文改进了Matsumoto和Ishikawa的工作，通过获得Atkinson型误差项显式公式，给出了临界带内黎曼zeta函数与Dirichlet多项式乘积均方值的渐近公式，与广义Dirichlet除数问题紧密相关。

On the symmetry of the k-divisors functions in short intervals

This paper has been withdrawn by the author, due to a crucial error in the proof of Thm.1

A note on the binary additive divisor problem

In this note we show that the methods of Motohashi and Meurman yield the same upper bound on the error term in the binary additive divisor problem. With this goal, we improve an estimate in the proof of Motohashi.

On the Dirichlet divisor problem in short intervals

We present several new results involving $Δ(x+U)-Δ(x)$, where $U = o(x)$ and $$ Δ(x):=\sum_{n\le x}d(n)-x\log x-(2γ-1)x $$ is the error term in the classical Dirichlet divisor problem.

On a certain additive divisor problem

We prove an asymptotic formula for a variant of the binary additive divisor problem with linear factors in the arguments, which has a power saving error term and which is uniform in all involved parameters.

On the $k$-free divisor problem

Let $Δ^{(k)}(x)$ denote the error term of the $k$-free divisor problem for $k\geq 2$. In this paper we establish an asymptotic formula of the integral $\int_1^T|Δ^{(k)}(x)|^2dx$ for each $k\geq 4.$

On the Riemann zeta-function and the divisor problem IV

Let $Δ(x)$ denote the error term in the Dirichlet divisor problem, and $E(T)$ the error term in the asymptotic formula for the mean square of $|ζ(1/2+it)|$. If $E^*(t) = E(t) - 2πΔ^*(t/(2π))$ with $Δ^*(x) = -Δ(x) + 2Δ(2x) - {1\over2}Δ(4x)$, then it is proved that $$ \int_0^T|E^*(t)|^3dt \ll_εT^{3/2+ε}, $$ which is (up to `$ε$' best possible) and $ζ(1/2+it) \ll_εt^{ρ/2+ε}$ if $E^*(t) \ll_εt^{ρ+ε}$.

On the Riemann zeta-function and the divisor problem II

First part of this paper was published in CEJM (2)(4) (2004), 1-15. It is proved now that $$ \int_0^T|E^*(t)|^5{\rm d}t \ll_εT^{2+ε}. $$ Here $$ E^*(t) = E(t) - 2πΔ^*(t/2π), Δ^*(x) = - Δ(x) +2Δ(2x) - {1\over2}Δ(4x), $$ where $E(t)$ is the error term in the mean square formula for $|ζ(1/2+it)|$ and $Δ(x)$ is the error term in the Dirichlet divisor problem. It is also shown how bounds for moments of $|E^*(t)|$ lead to bounds for moments of $|ζ(1/2+it)|$.

Recursive formulas for sums of squares and sums of triangular numbers

We prove recursive formulas for sums of squares and sums of triangular numbers in terms of sums of divisors functions and we give a variety of consequences of these formulas. Intermediate applications include statements about positivity of the coefficients of some infinite products.

On the greatest common divisor of the value of two polynomials

We show that if two monic polynomials with integer coefficients have square-free resultant, then all positive divisors of the resultant arise as the greatest common divisor of the values of the two polynomials at a suitable integer.

The shifted convolution of generalized divisor functions

We prove an asymptotic formula for the shifted convolution of the divisor functions $d_k(n)$ and $d(n)$ with $k \geq 4$, which is uniform in the shift parameter and which has a power-saving error term, improving results obtained previously by Fouvry and Tenenbaum and, more recently, by Drappeau.

Uniform bounds of Piltz divisor problem over number fields

We consider the upper bound of Piltz divisor problem over number fields. Piltz divisor problem is known as a generalization of the Dirichlet divisor problem. We deal with this problem over number fields and improve the error term of this function for many cases. Our proof uses the estimate of exponential sums. We also show uniform results for ideal counting function and relatively $r$-prime lattice points as one of applications.

数域上使用共振方法的Piltz除数问题

The Piltz divisor Problem in Number Fields Using The Resonance Method

本文在数域上研究Piltz除数问题，通过推广Soundararajan的Voronoi型公式并应用第二作者的近期结果，成功获得了误差项改进的$\Omega-$界。

Higher Correlations of Divisor Sums Related to Primes II: Variations of the error term in the prime number theorem

We calculate the triple correlations for the truncated divisor sum $λ_{R}(n)$. The $λ_{R}(n)$'s behave over certain averages just as the prime counting von Mangoldt function $Λ(n)$ does or is conjectured to do. We also calculate the mixed (with a factor of $Λ(n)$) correlations. The results for the moments up to the third degree, and therefore the implications for the distribution of primes in short intervals, are the same as those we obtained (in the first paper with this title) by using the simpler approximation $Λ_{R}(n)$. However, when $λ_{R}(n)$ is used the error in the singular series app…

Perfect powers that are sums of squares in a three term arithmetic progression

We determine primitive solutions to the equation $(x-r)^2 + x^2 + (x+r)^2 = y^n$ for $1 \le r \le 5,000$, making use of a factorization argument and the Primitive Divisors Theorem due to Bilu, Hanrot and Voutier.

On the Riemann zeta-function and the divisor problem III

Let $Δ(x)$ denote the error term in the Dirichlet divisor problem, and $E(T)$ the error term in the asymptotic formula for the mean square of $|ζ(1/2+it)|$. If $E^*(t) = E(t) - 2πΔ^*(t/2π)$ with $Δ^*(x) = -Δ(x) + 2Δ(2x) - {1\over2}Δ(4x)$ and we set $\int_0^T E^*(t) dt = 3πT/4 + R(T)$, then we obtain $$ R(T) = O_ε(T^{593/912+ε}), \int_0^TR^4(t) dt \ll_εT^{3+ε}, $$ and $$ \int_0^TR^2(t) dt = T^2P_3(\log T) + O_ε(T^{11/6+ε}), $$ where $P_3(y)$ is a cubic polynomial in $y$ with positive leading coefficient.

Square-root cancellation for sums of factorization functions over squarefree progressions in $\mathbb F_q[t]$

We prove estimates for the level of distribution of the Möbius function, von Mangoldt function, and divisor functions in squarefree progressions in the ring of polynomials over a finite field. Each level of distribution converges to $1$ as $q$ goes to $\infty$, and the power savings converges to square-root cancellation as $q$ goes to $\infty$. These results in fact apply to a more general class of functions, the factorization functions, that includes these three. The divisor estimates have applications to the moments of $L$-functions, and the von Mangoldt estimate to one-level densities.

Piltz除数问题的Omega界

Omega bound for the Piltz divisor problem

本文通过结合共振论证与计数定理，在数域上改进了Piltz除数问题误差项的omega界，并去除了先前界中的三次迭代对数因子。

The Shifted Convolution of Divisor Functions

We prove an asymptotic formula for the shifted convolution of the divisor functions $d_3(n)$ and $d(n)$, which is uniform in the shift parameter and which has a power-saving error term. The method is also applied to give analogous estimates for the shifted convolution of $d_3(n)$ and Fourier coefficents of holomorphic cusp forms. These asymptotics improve previous results obtained by several different authors.