In mathematical knot theory, a **Conway sphere**, named after John Horton Conway, is a 2-sphere intersecting a given knot in the 3-sphere or 3-ball transversely in four points. It is *essential* if it is incompressible and boundary-incompressible in the knot complement.

## References

- Gordon, Cameron McA.; Luecke, John (2006). "Knots with unknotting number 1 and essential Conway spheres".
*Alg. Geom. Topol*.**6**: 2051–2116. doi:10.2140/agt.2006.6.2051. Retrieved 1 May 2014. - Lickorish, W. B. Raymond (1997),
*An introduction to knot theory*, Graduate Texts in Mathematics,**175**, Berlin, New York: Springer-Verlag, ISBN 978-0-387-98254-0, MR 1472978

This page was last edited on 24 October 2016, at 05:53.