Julia Robinson numbers and arithmetical dynamic of quadratic polynomials
For rings $\mathcal{O}_K$ of totally real algebraic integers, J. Robinson defined a set which is always $\{+\infty\}$ or of the form $[λ,+\infty)$ or $(λ,+\infty)$ for some real number $λ\ge4$. All known examples give either $\{+\infty\}$ or $[4,+\infty)$. In this paper, we construct infinitely many fields such that the set is an interval, but not equal to $[4,+\infty)$.
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