If the Knot is the boundary of a singular disk which has the property that each self-intersecting component is an arc for which consists of two arcs in , one of which is interior, then is said to be a ribbon knot. Every ribbon knot is a Slice Knot, and it is conjectured that every Slice Knot is a ribbon knot.

**References**

Rolfsen, D. *Knots and Links.* Wilmington, DE: Publish or Perish Press, p. 225, 1976.

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1999-05-25