Hang Fu

activity

20162026

most citedDivision Polynomials and Intersection of Projective Torsion Points

6 citations · 12 across the 11 of their papers we have counts for

collaborators

11 papers

math.NT2026

On the noninjectivity of Jordan's totient functions

Hang Fu

For any positive integer $k$ , let $J_{k}$ be Jordan's totient function. We show that $J_{k}$ is not injective when $k = 3, 4, 6$ .

math.DS2023

Böttcher coordinates at wild superattracting fixed points

Hang Fu, Hongming Nie

Let $p$ be a prime number, let $g (x) = x^{p^{2}} + p^{r + 2} x^{p^{2} + 1}$ with $r \in Z_{\geq 0}$ , and let $ϕ (x) = x + O (x^{2})$ be the Böttcher coordinate satisfying $ϕ(g(x))=ϕ(x)^{p^{…

math.NT2022

Dynamics of quadratic polynomials and rational points on a curve of genus $4$

Hang Fu, Michael Stoll

Let $f_{t} (z) = z^{2} + t$ . For any $z \in Q$ , let $S_{z}$ be the collection of $t \in Q$ such that $z$ is preperiodic for $f_{t}$ . In this article, assuming a well-known conject…

math.NT2020

Uniform unlikely intersections for unicritical polynomials

Hang Fu

Fix $d \geq 2$ , and consider the family $f_{t} (z) = z^{d} + t$ of polynomials parameterized by $t \in C$ . In this article, we will show that there exists a constant $C (d)$ such th…

math.AG2019★ 3 cited

Elliptic curves with common torsion $x$ -coordinates and hyperelliptic torsion packets

Hang Fu, Michael Stoll

We establish a connection between torsion packets on curves of genus $2$ and pairs of elliptic curves realized as double covers of the projective line $P_{x}^{1}$ that hav…

math.NT2019★ 1 cited

Projective Equivalence for the Roots of Unity

Hang Fu

Let $μ_{\infty} \subseteq C$ be the collection of roots of unity and $\mathcal{C}_{n}:=\{(s_{1},\cdots,s_{n})\inμ_{\infty}^{n}:s_{i}\neq s_{j}\text{ for any }1\leq i<j\leq n…

math.AG2019

On the $PGL_{2}$ -invariant quadruples of torsion points of elliptic curves

Fedor Bogomolov, Hang Fu

Let $E$ be an elliptic curve and $π : E \to P^{1}$ a standard double cover identifying $\pm P \in E$ . It is known that for some torsion points $P_{i} \in E$ , $1 \leq i \leq 4$ , the…

math.AG2018

Noether's problem for some subgroups of $S_{14}$ : the modular case

Hang Fu, Ming-chang Kang, Baoshan Wang +1

Let $G$ be a subgroup of $S_{n}$ , the symmetric group of degree $n$ . For any field $k$ , $G$ acts naturally on the rational function field $k (x_{1}, \dots, x_{n})$ via $k$ -automorphi…

math.AG2017

Torsion of elliptic curves and unlikely intersections

Fedor Bogomolov, Hang Fu, Yuri Tschinkel

We study effective versions of unlikely intersections of images of torsion points of elliptic curves on the projective line.

math.NT2017★ 2 cited

Elliptic Curves with Large Intersection of Projective Torsion Points

Fedor Bogomolov, Hang Fu

We construct pairs of elliptic curves over number fields with large intersection of projective torsion points.

math.NT2016★ 6 cited

Division Polynomials and Intersection of Projective Torsion Points

Fedor Bogomolov, Hang Fu

Given two elliptic curves, each of which is associated with a projection map that identifies opposite elements with respect to the natural group structure, we investigate how their…

On the noninjectivity of Jordan's totient functions

Böttcher coordinates at wild superattracting fixed points

Dynamics of quadratic polynomials and rational points on a curve of genus 4

Uniform unlikely intersections for unicritical polynomials

Elliptic curves with common torsion x-coordinates and hyperelliptic torsion packets

Projective Equivalence for the Roots of Unity

On the PGL2​-invariant quadruples of torsion points of elliptic curves

Noether's problem for some subgroups of S14​: the modular case

Torsion of elliptic curves and unlikely intersections

Elliptic Curves with Large Intersection of Projective Torsion Points

Division Polynomials and Intersection of Projective Torsion Points

Dynamics of quadratic polynomials and rational points on a curve of genus $4$

Elliptic curves with common torsion $x$ -coordinates and hyperelliptic torsion packets

On the $PGL_{2}$ -invariant quadruples of torsion points of elliptic curves

Noether's problem for some subgroups of $S_{14}$ : the modular case