QES systems, invariant spaces and polynomials recursions

Y. Brihaye, J. Ndimubandi, B. Prasad Mandal

Let us denote $\mathcal{V}$, the finite dimensional vector spaces of functions of the form $\psi (x)=p_n(x)+f(x)p_m(x)$ where $p_n(x)$ and $p_m(x)$ are arbitrary polynomials of degre…