Numerical characterization of nef arithmetic divisors on arithmetic surfaces

Atsushi Moriwaki

Displaying similar documents to “Numerical characterization of nef arithmetic divisors on arithmetic surfaces”

Some properties of the class of arithmetic functions $T_{r} (N)$

R. P. Pakshirajan (1963)

Annales Polonici Mathematici

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On generalized square-full numbers in an arithmetic progression

Angkana Sripayap, Pattira Ruengsinsub, Teerapat Srichan (2022)

Czechoslovak Mathematical Journal

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Let $a$ and $b \in ℕ$ . Denote by $R_{a, b}$ the set of all integers $n > 1$ whose canonical prime representation $n = p_{1}^{α_{1}} p_{2}^{α_{2}} \dots p_{r}^{α_{r}}$ has all exponents $α_{i}$ $(1 \leq i \leq r)$ being a multiple of $a$ or belonging to the arithmetic progression $a t + b$ , $t \in ℕ_{0} : = ℕ \cup {0}$ . All integers in $R_{a, b}$ are called generalized square-full integers. Using the exponent pair method, an upper bound for character sums over generalized square-full integers is derived. An application on the distribution of generalized square-full integers in an arithmetic progression is given. ...

On a certain class of arithmetic functions

Antonio M. Oller-Marcén (2017)

Mathematica Bohemica

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A homothetic arithmetic function of ratio $K$ is a function $f : ℕ \to R$ such that $f (K n) = f (n)$ for every $n \in ℕ$ . Periodic arithmetic funtions are always homothetic, while the converse is not true in general. In this paper we study homothetic and periodic arithmetic functions. In particular we give an upper bound for the number of elements of $f (ℕ)$ in terms of the period and the ratio of $f$ .

On the least almost-prime in arithmetic progressions

Liuying Wu (2024)

Czechoslovak Mathematical Journal

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Let $𝒫_{2}$ denote a positive integer with at most $2$ prime factors, counted according to multiplicity. For integers $a$ , $q$ such that $(a, q) = 1$ , let $𝒫_{2} (q, a)$ denote the least $𝒫_{2}$ in the arithmetic progression ${n q + a}_{n = 1}^{\infty}$ . It is proved that for sufficiently large $q$ , we have $𝒫_{2} (q, a) ≪ q^{1.825} .$ This result constitutes an improvement upon that of J. Li, M. Zhang and Y. Cai (2023), who obtained $𝒫_{2} (q, a) ≪ q^{1.8345} .$

Coprimality of integers in Piatetski-Shapiro sequences

Watcharapon Pimsert, Teerapat Srichan, Pinthira Tangsupphathawat (2023)

Czechoslovak Mathematical Journal

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We use the estimation of the number of integers $n$ such that $⌊ n^{c} ⌋$ belongs to an arithmetic progression to study the coprimality of integers in $ℕ^{c} = {⌊ n^{c} ⌋}_{n \in ℕ}$ , $c > 1$ , $c \notin ℕ$ .

A problem of Rankin on sets without geometric progressions

Melvyn B. Nathanson, Kevin O'Bryant (2015)

Acta Arithmetica

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A geometric progression of length k and integer ratio is a set of numbers of the form $a, a r, . . ., a r^{k - 1}$ for some positive real number a and integer r ≥ 2. For each integer k ≥ 3, a greedy algorithm is used to construct a strictly decreasing sequence ${(a_{i})}_{i = 1}^{\infty}$ of positive real numbers with a₁ = 1 such that the set $G^{(k)} = ⋃_{i = 1}^{\infty} (a_{2 i}, a_{2 i - 1}]$ contains no geometric progression of length k and integer ratio. Moreover, $G^{(k)}$ is a maximal subset of (0,1] that contains no geometric progression of length k and integer ratio. It is also proved that...

The Golomb space is topologically rigid

Taras O. Banakh, Dario Spirito, Sławomir Turek (2021)

Commentationes Mathematicae Universitatis Carolinae

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The Golomb space $ℕ_{τ}$ is the set $ℕ$ of positive integers endowed with the topology $τ$ generated by the base consisting of arithmetic progressions ${a + b n : n \geq 0}$ with coprime $a, b$ . We prove that the Golomb space $ℕ_{τ}$ is topologically rigid in the sense that its homeomorphism group is trivial. This resolves a problem posed by T. Banakh at Mathoverflow in 2017.

On a sum involving the integral part function

Bo Chen (2024)

Czechoslovak Mathematical Journal

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Let $[t]$ be the integral part of a real number $t$ , and let $f$ be the arithmetic function satisfying some simple condition. We establish a new asymptotical formula for the sum $S_{f} (x) = \sum_{n \leq x} f ([x / n])$ , which improves the recent result of J. Stucky (2022).

General position properties in fiberwise geometric topology

Taras Banakh, Vesko Valov

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General position properties play a crucial role in geometric and infinite-dimensional topologies. Often such properties provide convenient tools for establishing various universality results. One of well-known general position properties is DDⁿ, the property of disjoint n-cells. Each Polish $L C^{n - 1}$ -space X possessing DDⁿ contains a topological copy of each n-dimensional compact metric space. This fact implies, in particular, the classical Lefschetz-Menger-Nöbeling-Pontryagin-Tolstova embedding...

An arithmetic Riemann-Roch theorem for pointed stable curves

Gérard Freixas Montplet (2009)

Annales scientifiques de l'École Normale Supérieure

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Let $(𝒪, Σ, F_{\infty})$ be an arithmetic ring of Krull dimension at most 1, $𝒮 = Spec 𝒪$ and $(π : 𝒳 \to 𝒮; σ_{1}, ..., σ_{n})$ an $n$ -pointed stable curve of genus $g$ . Write $𝒰 = 𝒳 ∖ \cup_{j} σ_{j} (𝒮)$ . The invertible sheaf $ω_{𝒳 / 𝒮} (σ_{1} + \dots + σ_{n})$ inherits a hermitian structure ${∥ \cdot ∥}_{hyp}$ from the dual of the hyperbolic metric on the Riemann surface $𝒰_{\infty}$ . In this article we prove an arithmetic Riemann-Roch type theorem that computes the arithmetic self-intersection of $ω_{𝒳 / 𝒮} {(σ_{1} + ... + σ_{n})}_{hyp}$ . The theorem is applied to modular curves $X (Γ)$ , $Γ = Γ_{0} (p)$ or $Γ_{1} (p)$ , $p \geq 11$ prime, with sections given by the cusps. We show $Z^{'} (Y (Γ), 1) \sim e^{a} π^{b} Γ_{2} {(1 / 2)}^{c} L (0, ℳ_{Γ})$ , with $p \equiv 11 m o d 12$ when $Γ = Γ_{0} (p)$ . Here $Z (Y (Γ), s)$ is the Selberg...

A structure theorem for sets of small popular doubling

Przemysław Mazur (2015)

Acta Arithmetica

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We prove that every set A ⊂ ℤ satisfying $\sum_{x} m i n (1_{A} * 1_{A} (x), t) \leq (2 + δ) t | A |$ for t and δ in suitable ranges must be very close to an arithmetic progression. We use this result to improve the estimates of Green and Morris for the probability that a random subset A ⊂ ℕ satisfies |ℕ∖(A+A)| ≥ k; specifically, we show that $ℙ (| ℕ ∖ (A + A) | \geq k) = Θ (2^{- k / 2})$ .