Positivity in coefficient-free rank two cluster algebras

G. Dupont

Let $b,c$ be positive integers, $x_1,x_2$ be indeterminates over $\mathbb{Z}$ and $x_m,m\in \mathbb{Z}$ be rational functions defined by $x_{m-1}{x}_{m+1}=x_m^b+1$ if $m$ is odd and $x_{m-1…