The generalized slice-ribbon conjecture for links and handlebodies

Let a link in $S^3$ be ribbon when it bounds a ribbon surface and slice when it bounds a slice surface, and let the ribbon and slice genera be the corresponding minimal genera. Generalized slice-ribbon conjecture. \begin{itemize} \item A link inS^3$is ribbon if and only if it is slice. \item In$S^3the ribbon genus coincides with the slice genus. \item The previous facts hold also for different ambient 4-manifolds, for instance 4-dimensional orientable handlebodies. \end{itemize} These are proposed generalizations of the knot version; the supplied text gives no resolution.