A crossing in aknot diagram for which there exists a circle in the projection plane meeting the diagram transversely at that crossing, but not meeting the diagram at any other point. Removable crossings can be removed by twisting, and so cannot occur in aknot diagram of minimallink crossing number. Reducible crossings are also called nugatory crossings (Tait 1898, Hosteet al.1998) or removable crossings.

See also

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References

Hoste, J.; Thistlethwaite, M.; and Weeks, J. "The First Knots."Math. Intell.20, 33-48, Fall 1998.

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Cite this as:

Weisstein, Eric W. "Reducible Crossing."FromMathWorld--A Wolfram Web Resource.https://mathworld.wolfram.com/ReducibleCrossing.html

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