Let $F<E$ be an algebraic field extension. Let $\alpha\in E$ be such that $\min(\alpha,F)$ has only one root in $E$ (which will be $\alpha$).Is it true that for any $p(x)\in F[x]$ we must have: "$\min(p(\alpha),F)$ has only one root in $E$" Another question: Does the above conjecture at least hold in characteristic $0$ ? Thank you a lot. (Note: $\min(\alpha,F)$ denotes the minimal monic polynomial of $\alpha$ over $F$)