In 2001, motivated by his results on finite-type knot diagram invariants, Östlund conjectured that Reidemeister moves 1 and 3 are sufficient to describe a homotopy from any generic immersion S¹ → ℝ² to the standard embedding of the circle. We show that this conjecture is false.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-bc103-0-4, author = {Tobias Hagge and Jonathan Yazinski}, title = {On the necessity of Reidemeister move 2 for simplifying immersed planar curves}, journal = {Banach Center Publications}, volume = {102}, year = {2014}, pages = {101-110}, zbl = {1314.14055}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc103-0-4} }
Tobias Hagge; Jonathan Yazinski. On the necessity of Reidemeister move 2 for simplifying immersed planar curves. Banach Center Publications, Tome 102 (2014) pp. 101-110. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-bc103-0-4/