Sub-chord diagrams of knot projections

Noboru Ito, Yusuke Takimura

研究成果: Article

4 引用 (Scopus)

抜粋

A chord diagram is a circle with paired points with each pair of points connected by a chord. Every generic immersed spherical curve pro- vides a chord diagram by associating each chord with two preimages of a double point. Any two spherical curves can be related by a finite sequence of three types of local replacement RI, RII, and RIII, called Reidemeister moves. This study counts the difference in the numbers of sub-chord dia- grams embedded in a full chord diagram of any spherical curve by applying one of the moves RI, strong RII, weak RII, strong RIII, and weak RIII defined by connections of branches related to the local replacements (Theorem 1.1). This yields a new integer-valued invariant under RI and strong RIII that provides a complete classification of prime reduced spherical curves with up to at least seven double points (Theorem 1.2, Fig. 24): there has been no such invariant before. The invariant expresses the necessary and sufficient condition that spherical curves can be related to a simple closed curve by a finite sequence consisting of RI and strong RIII (Theorem 1.3). Moreover, in- variants of spherical curves under ypes are provided by counting sub-chord diagrams (Theorem 1.4).

元の言語English
ページ(範囲)701-725
ページ数25
ジャーナルHouston Journal of Mathematics
41
発行部数2
出版物ステータスPublished - 2015
外部発表Yes

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ASJC Scopus subject areas

  • Mathematics(all)

これを引用

Ito, N., & Takimura, Y. (2015). Sub-chord diagrams of knot projections. Houston Journal of Mathematics, 41(2), 701-725.