A certain magma of natural numbers
Source:
December 13, 2019
algebraabstract algebraDivisibilitynumber theory
Problem Statement
Determine all sets of natural numbers that have at least two elements, and satisfying the following proposition:
\forall x,y\in A x>y\implies \frac{x-y}{\text{gcd} (x,y)} \in A.
Marius Perianu