Hyunjun Yi

collaborators

4 papers

math.MG2026

Isosceles sets in Euclidean spaces of dimension nine to twenty-two

Hyunjun Yi

A finite set of points in $R^{d}$ is isosceles if every three of its points form an isosceles triangle. Erdős asked in 1946 for the largest size $iso (d)$ of an isos…

math.CO2026

Johnson optimality and uniqueness for distance ratio $1 : 2$

Bryan Bu, Chin-Yen Lee, Yu-Hang Sheng +3

We prove that a two-distance set in $R^{d}$ with distance ratio $1 : 2$ has at most $d (d + 1) /2$ points for every $d \geq 9$ . Equality in full affine dimension characterizes…

math.CO2026

Four runners that are barely lonely

Hyunjun Yi, Karam Gill, Bryan Bu

For positive integers $v_{1}, \dots, v_{n}$ let $ML (v_{1}, \dots, v_{n}) = max_{t} min_{i} ∥ v_{i} t ∥$ , where $∥ x ∥$ is the distance to the nearest integer. Kravitz asked which values below…

math.NT2026

A Half-Constant Upper Bound for Chowla's Cosine Problem

Bryan Bu, Fayzan Khan, Hyunjun Yi +4

Let lambda(n) denote the infimum of -min_x sum_{a in A} cos(ax) over all sets A of n positive integers. While the classical Sidon-difference construction yields lambda(n) <= (1 + o…

Isosceles sets in Euclidean spaces of dimension nine to twenty-two

Johnson optimality and uniqueness for distance ratio 1:2​

Four runners that are barely lonely

A Half-Constant Upper Bound for Chowla's Cosine Problem

Johnson optimality and uniqueness for distance ratio $1 : 2$