Unlink

The unlink, also called the trivial link, of  components consist of  disjoint circles in a plane (Rolfsen 1976, p. 65).

REFERENCES:

Adams, C. C. The Knot Book: An Elementary Introduction to the Mathematical Theory of Knots. New York: W. H. Freeman, p. 18, 1994.

Livingston, C. Knot Theory. Washington, DC: Math. Assoc. Amer., p. 16, 1993.

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