Regular isotopy is the equivalence relation on knot diagrams and link diagrams generated by planar deformations preserving crossing information and Reidemeister moves of types II and III (Kauffman 1990, pp. 417-418). Unlike ambient isotopy, it excludes the type I Reidemeister move.
Regular Isotopy
See also
Ambient Isotopy, Reidemeister MovesExplore with Wolfram|Alpha
References
Kauffman, L. H. "An Invariant of Regular Isotopy." Trans. Amer. Math. Soc. 318, 417-471, 1990.Referenced on Wolfram|Alpha
Regular IsotopyCite this as:
Weisstein, Eric W. "Regular Isotopy." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/RegularIsotopy.html