Paper detail

"Slicing" the Hopf link

A link in the 3-sphere is called (smoothly) slice if its components bound disjoint smoothly embedded disks in the 4-ball. More generally, given a 4-manifold M with a distinguished circle in its boundary, a link in the 3-sphere is called M-slice if its components bound in the 4-ball disjoint embedded copies of M. A 4-manifold M is constructed such that the Borromean rings are not M-slice but the Hopf link is. This contrasts the classical link-slice setting where the Hopf link may be thought of "the most non-slice" link. Further examples and an obstruction for a family of decompositions of the 4-ball are discussed in the context of the A-B slice problem.