Junnosuke Koizumi

collaborators

5 papers

math.CO2025

At most 10 cylinders mutually touch: a Ramsey-theoretic approach

Travis Dillon, Junnosuke Koizumi, Sammy Luo

Littlewood asked for the maximum number $N$ of congruent infinite cylinders that can be arranged in $R^{3}$ so that every pair touches. We improve upon the proof of the seco…

math.NT2025

Irreducibility of polynomials defining parabolic parameters of period 3

Junnosuke Koizumi, Yuya Murakami, Kaoru Sano +1

Morton and Vivaldi defined the polynomials whose roots are parabolic parameters for a one-parameter family of polynomial maps. We call these polynomials delta factors. They conject…

math.MG2025

A new upper bound for mutually touching infinite cylinders

Junnosuke Koizumi

Let $N$ denote the maximum number of congruent infinite cylinders that can be arranged in $R^{3}$ so that every pair of cylinders touches each other. Littlewood posed the qu…

math.CA2025

Isosceles trapezoids of unit area with vertices in sets of infinite planar measure

Junnosuke Koizumi

Paul ErdÅs posed the question of whether every measurable planar set of infinite Lebesgue measure contains the four vertices of an isosceles trapezoid of unit area. In this paper,…

math.CO2024

A note on the ErdÅs conjecture about square packing

Jineon Baek, Junnosuke Koizumi, Takahiro Ueoro

Let $f (n)$ denote the maximum total length of the sides of $n$ squares packed inside a unit square. ErdÅs conjectured that $f (k^{2} + 1) = k$ . We show that the conjecture is true if we…

At most 10 cylinders mutually touch: a Ramsey-theoretic approach

Irreducibility of polynomials defining parabolic parameters of period 3

A new upper bound for mutually touching infinite cylinders

Isosceles trapezoids of unit area with vertices in sets of infinite planar measure

A note on the ErdÅs conjecture about square packing

A note on the ErdÅs conjecture about square packing