On some modular identities (original) (raw)

A note on generating identities for multiplicative arithmetic functions

Contributions to mathematics, 2023

In this article, it is shown that many of the identities involving multiplicative arithmetic functions are special cases of a more general formula. The approach employed in this article avoids using classical techniques, including Dirichlet's convolution.

Convolution identities for divisor sums and modular forms

arXiv (Cornell University), 2023

We prove exact identities for convolution sums of divisor functions of the form n1∈Z {0,n} ϕ(n 1 , n − n 1)σ 2m1 (n 1)σ 2m2 (n − n 1) where ϕ(n 1 , n 2) is a Laurent polynomial with logarithms for which the sum is absolutely convergent. Such identities are motivated by computations in string theory and prove and generalize a conjecture of Chester, Green, Pufu, Wang, and Wen from [6]. Originally, it was suspected that such sums, suitably extended to n 1 ∈ {0, n} should vanish, but in this paper we find that in general they give Fourier coefficients of holomorphic cusp forms.

The arithmetic of the values of modular functions and the divisors of modular forms

Compositio Mathematica, 2004

We investigate the arithmetic and combinatorial significance of the values of the polynomials j n (x) defined by the q-expansion ∞ n=0 j n (x)q n := E 4 (z) 2 E 6 (z) ∆(z) • 1 j(z) − x. They allow us to provide an explicit description of the action of the Ramanujan Thetaoperator on modular forms. There are a substantial number of consequences for this result. We obtain recursive formulas for coefficients of modular forms, formulas for the infinite product exponents of modular forms, and new p-adic class number formulas.

Arithmetic of generalized Dedekind sums and their modularity

Open Mathematics

Dedekind sums were introduced by Dedekind to study the transformation properties of Dedekind η function under the action of SL2(ℤ). In this paper, we study properties of generalized Dedekind sums si,j(p, q). We prove an asymptotic expansion of a function on ℚ defined in terms of generalized Dedekind sums by using its modular property. We also prove an equidistribution property of generalized Dedekind sums.

Some Recurrences for Arithmetical Functions

Journal of the Indian Mathematical Society

Euler proved the following recurrence for p(n), the number of partitions of an integer n : (1) p(n) + ∞ X k=1 (−1) k (p(n − ω(k)) + p(n − ω(−k))) = 0 for ω(k) = 3k 2 +k 2. Using the Jacobi Triple Product identity we show analogues of Euler's recurrence formula for common restricted partition functions. Moreover following Kolberg, these recurrences allow us to determine that these partition functions are both even and odd infinitely often. Using the theory of modular forms, these recurrences may be viewed as infinite product identities involving Dedekind's η-function. Specifically, if the generating function for an arithmetical function is a modular form, then one often obtains analogous recurrence formulas; in particular here we get recurrence relations involving the number of t-core partitions, the number of representations of sums of squares, certain divisor functions, the number of points in finite fields on certain elliptic curves with complex multiplication, the Ramanujan τ −function and some appropriate analogs. In some cases recurrences hold for almost all n, and in others these recurrences hold for all n where the equality is replaced by a congruence mod m for any fixed integer m. These new recurrences are consequences of some of the theory of modular forms as developed by Deligne, Ribet, Serre, and Swinnerton-Dyer. p(n) ∼ 1 4n √ 3 e π √ 2n 3

Certain aspects of some arithmetic functions in number theory

The purpose of this paper is to present several inequalities about the arithmetic functions σ (e) ,τ (e) ,σ (e)* ,τ (e)* and other well-known arithmetic functions. Among these, we have the following: σ k * (n)·σ l * (n) σ k-l 2 * (n)≤n l-k 4 ·σ k * (n)+n k-l 4 ·σ l * (n) 2·σ k-l 2 (n)≤n l-k 4 ·n k+l 2 +1 2, for any n,k,l∈ℕ * , σ k (e)* (n)·τ (e)* (n) σ k-l 2 (e)* (n)≤n l-k 4 ·σ k (e)* (n)+n k-l 4 ·τ (e)* (n) 2·σ k-l 2 (e)* (n)≤n l-k 4 ·n k+l 2 +1 2, for any n,k,l∈ℕ * , σ k (e) (n)·σ l (e) (n)≤τ (e) (n)·τ k+l (e) (n) for any n,k,l∈ℕ * and σ k+1 (e)* (n) σ k (e)* (n)≥σ (e)* (n) τ (e)* (n)≥τ(n) for any n,k∈ℕ * , where τ(n) is the number of the natural divisors of n and σ(n) is the sum of the divisors of n.

Arithmetic properties arising from Ramanujan’s theta functions

The Ramanujan Journal, 2016

We prove some interesting arithmetic properties of theta function identities that are analogous to q-series identities obtained by Michael D. Hirschhorn. In addition, we find infinite family of congruences modulo powers of 2 for representations of a non-negative integer n as 1 + 4 2 and + k .

Some Modular Relations Analogues to the Ramanujan’s Forty Identities with Its Applications to Partitions

Recently, the authors have established a large class of modular relations involving the Rogers-Ramanujan type functions J(q) and K(q) of order ten. In this paper, we establish further modular relations connecting these two functions with Rogers-Ramanujan functions, Göllnitz-Gordon functions and cubic functions, which are analogues to the Ramanujan's forty identities for Rogers-Ramanujan functions. Furthermore, we give partition theoretic interpretations of some of our modular relations.

Remarks of Congruent Arithmetic Sums of Theta Functions Derived from Divisor Functions

Honam Mathematical Journal, 2013

In this paper, we study a distinction the two generating functions : ϕ k (q) = ∞ n=0 r k (n)q n and ϕ * ,k (q) = ϕ k (q) − ϕ k (q 2) (k = 2, 4, 6, 8, 10, 12, 16), where r k (n) is the number of representations of n as the sum of k squares. We also obtain some congruences of representation numbers and divisor function.