Core disk of a handle
= Core disk of a handle
{title2=$D^k\times\{0\}$}
= Core disks of handles
{synonym}
The core disk of a $k$-<handle attachment> $D^k\times D^{n-k}$ is $D^k\times\{0\}$. Together with its cap in the preceding stage, it often represents a <homology class>; for a <surgery trace>, capped two-handle cores give the basis of its <surgery linking matrix>.