Ribbon minimality conjecture for the 4-twisted Whitehead link

Let $W_4$ denote the 4-twisted Whitehead link, a two-component link formed from the fourth twist knot and an unknot. Ribbon minimality conjecture. The link $W_4$ is ribbon minimal. Theorem-level results leave $W_4$ and its mirror as the possible exceptions among twisted Whitehead links; the authors were unable to decide this case using link Floer homology, and relate it to the existence of slice disks for the knot $6_1$ modulo local knotting.