Describing subalgebras of $\mathbb{K}[x]$ using derivatives

Rode Grönkvist, Erik Leffler, Anna Torstensson +1

We introduce the concept of subalgebra spectrum, $Sp(A)$, for a subalgebra $A$ of finite codimension in $\mathbb{K}[x]$. The spectrum is a subset of the underlying field. We also i…