Meridian-link characterization of ribbon minimal knots

Let $K$ be a knot in $S^3$, and let $\mu_K$ be a meridian of $K$. Define the two-component link

$$L_K=K\sqcup\mu_K.$$

A link is ribbon concordance minimal if it has no strictly smaller link under ribbon concordance, and a knot is ribbon minimal if it has no strictly smaller knot under ribbon concordance. Meridian-link conjecture. The link $L_K$ is ribbon concordance minimal if and only if $K$ is ribbon minimal. The authors state that this conjecture is unproved and expect a general resolution to have applications to the study of minimality of satellite knots.