Poo-Sung Park

activity

20072026

most citedThe Fifteen Theorem for Universal Hermitian Lattices over Imaginary Quadratic Fields

5 citations · 15 across the 15 of their papers we have counts for

collaborators

16 papers

math.NT2026

The Fibonacci numbers are not an additive uniqueness set for multiplicative functions

Poo-Sung Park

Let $(F_{n})_{n \geq 0}$ be the Fibonacci sequence. We show that a multiplicative function $f$ satisfying \[ f(F_n+F_m)=f(F_n)+f(F_m)\qquad(n,m\geq 1) \] need not be the identity func…

math.NT2023

On multiplicative functions which are additive on positive cubes

Poo-Sung Park

Let $k \geq 3$ . If a multiplicative function $f$ satisfies \[ f(a_1^3 + a_2^3 + \cdots + a_k^3) = f(a_1^3) + f(a_2^3) + \cdots + f(a_k^3) \] for all $a_1, a_2, \ldots, a_k \in \mat…

math.NT2022

Multiplicative functions commutable with binary quadratic forms $x^{2} \pm x y + y^{2}$

Poo-Sung Park

If a multiplicative function $f$ is commutable with a quadratic form $x^{2} + x y + y^{2}$ , i.e., \[ f(x^2+xy+y^2) = f(x)^2 + f(x)\,f(y) + f(y)^2, \] then $f$ is the identity function. In o…

math.NT2020

Multiplicative functions with $f (p + q - n_{0}) = f (p) + f (q) - f (n_{0})$

Poo-Sung Park

Let $n_{0}$ be 1 or 3. If a multiplicative function $f$ satisfies $f (p + q - n_{0}) = f (p) + f (q) - f (n_{0})$ for all primes $p$ and $q$ , then $f$ is the identity function $f (n) = n$ or a constant…

math.NT2019

Multiplicative functions which are additive on sums of two nonzero squares

Poo-Sung Park

Let $f$ be a multiplicative function which satisfies \[ f(a^2+b^2+c^2+d^2) = f(a^2+b^2)+f(c^2+d^2) \] for positive integers $a$ , $b$ , $c$ , and $d$ . We show that $f$ is the identity…

math.NT2017

Multiplicative functions which are additive on triangular numbers

Poo-Sung Park

Fix $k \geq 3$ . If a multiplicative function $f$ satisfies \[ f(x_1+x_2+\dots+x_k) = f(x_1) + f(x_2) + \dots + f(x_k) \] for arbitrary positive triangular numbers $x_1, x_2, \dots,…

The Fibonacci numbers are not an additive uniqueness set for multiplicative functions

On multiplicative functions which are additive on positive cubes

Multiplicative functions commutable with binary quadratic forms x2±xy+y2

Multiplicative functions with f(p+q−n0​)=f(p)+f(q)−f(n0​)

Multiplicative functions which are additive on sums of two nonzero squares

Multiplicative functions which are additive on triangular numbers

Multiplicative functions commutable with binary quadratic forms $x^{2} \pm x y + y^{2}$

Multiplicative functions with $f (p + q - n_{0}) = f (p) + f (q) - f (n_{0})$