I've been looking around and haven't found anything on this topic so I figured I'd ask here.
Let $Z(x)$ and $R(x)$ be the rational functions over the integers and real respectively.
Does there exist a norm on $Z(x)$ (or $R(x)$) such that there exist a $p\in Z(x)$ (or $R(x)$) so that for all $n\in N$ we have $||p^{n+1}||< ||p^{n}||$?
Furthermore assuming the norm we are looking for in the above paragraph does exist, can we then find a norm on the algebraic closure of $Z(x)$ (or $R(x)$) so that it agrees with the previous norm when the domain is restricted to the rational functions?

