This question is about the relation between the notions of boundary link and ribbon link.
For the definition of ribbon link see: ribbon links - counterexamplesribbon links - counterexamples.
An n-component link $L=L_1\cup\dots\cup L_n$ is said to be a boundary link if there exists an orientable surface consisting of n disjoint components $S=S_1\cup\dots\cup S_n$ such that for each $i\leq n$ we have $\partial S_i=L_i$.
There exists boundary links which are not ribbon and ribbon links which are not boundary (see Rolfsen book chapter 5 pag. 140)
It can be shown that every pure ribbon link is a boundary link. (A ribbon link is said to be pure if every ribbon singularity involves only one disc.)
Now my problem is: when is a boundary link ribbon? Clearly every component of such a link must be a ribbon knot so my question is:
- $\textbf{Is every boundary link with ribbon components a ribbon link?}$
Assume the answer to the previous question is yes. Then the following question makes sense:
- $\textbf{Is it true that a link is purely ribbon iff it is a boundary link}$ $\textbf{ with ribbon components?}$