Biorthonormal Systems in Freud-type Weighted Spaces with Infinitely Many   Zeros - An Interpolation Problem
  In a Freud-type weighted ($w$) space, introducing another weight ($v$) with infinitely many roots, we give a complete and minimal system with respect to $vw$, by deleting infinitely many elements from the original orthonormal system with respect to $w$. The construction of the conjugate system implies an interpolation problem at infinitely many nodes. Besides the existence, we give some convergence properties of the solution. 
\'Agota P. Horv\'ath