Functional Decomposition using Principal Subfields

Luiz E. Allem, Juliane Capaverde, Mark van Hoeij +1

Let $f\in K(t)$ be a univariate rational function. It is well known that any non-trivial decomposition $g\circ h$, with $g,h\in K(t)$, corresponds to a non-trivial subfield $K(f(t…