La science et l'hypothèse
《La science et l'hypothèse》 · 第 210 页 · Section 6.2，Definition 6.2.3 中 ribbon surface、ribbon disk 与 ribbon knot 的定义
A smooth surface \((F,\partial F)\subset(D^4,S^3)\) is called a ribbon surface (or ribbon disk if \(F\approx D^2\)) if it can be isotoped (with \(\partial F\subset S^3\)) so that the height function \(D^4=I\times D^3\to I\) induces a handle decomposition without 2-handles (and \(\partial F\subset\{1\}\times D^3\)). Boundaries of ribbon disks are called ribbon knots, and similarly, ribbon links bound ribbon surfaces which are disjoint unions of disks.