MathDB
Ceiling in FE

Source: BdMO 2024 Higher Secondary National P7

March 18, 2024
functional equationceiling functionnumber theoryalgebra

Problem Statement

Find all functions f:NNf:\mathbb{N} \to \mathbb{N} such thatf(f(m)n)=mf(n)f\left(\Big \lceil \frac{f(m)}{n} \Big \rceil\right)=\Big \lceil \frac{m}{f(n)} \Big \rceilfor all m,nNm,n \in \mathbb{N}.
Proposed by Md. Ashraful Islam Fahim