×

The structure of a minimal \(n\)-chart with two crossings. I: Complementary domains of \({\Gamma}_1 \cup {\Gamma}_{n - 1}\). (English) Zbl 1408.57025

Take a closed surface \(F \subset \mathbb R^4\), i.e. 2-knot. Let \(p_1:\mathbb R^4 \to \mathbb R^3\) be a generic projection. \(p_1|_F\) has singularities which are double points, triple points and branch points. As the next step consider a plane \(P \subset \mathbb R^3\) such that \(p_1(F) \subset \mathbb R^3 \setminus P\) and a projection \(p_2:\mathbb R^3 \to P\). Then the image of \(p_2 p_1\) of the fold lines and cusps forms an oriented graph \(\Gamma\) called the chart. Every vertex of \(\Gamma\) has degree 1 (black vertex), 4 (crossing) or 6 (white vertex). A chart of degree \(n\) has edges labeled from 1 to \(n-1\). From a chart we can construct the closed surface.
The paper, at its introduction, has a list of terms and symbols that is quite useful. Therefore we will not introduce other terms and notions but quote a sentence from the paper: “We investigate the structure of minimal charts with two crossings and give an enumeration of the charts with two crossings.”

MSC:

57Q45 Knots and links in high dimensions (PL-topology) (MSC2010)
57Q35 Embeddings and immersions in PL-topology

References:

[1] Carter, J. S.; Saito, M., Knotted Surfaces and Their Diagrams, 55, (1998), American Mathematical Society: American Mathematical Society, Providence, RI · Zbl 0904.57010
[2] Kamada, S., Surfaces in \(R^4\) of braid index three are ribbon, J. Knot Theory Ramifications, 1, 2, 137-160, (1992) · Zbl 0763.57013
[3] S. Kamada, \(2\)-dimensional braids and chart descriptions, Topics in Knot Theory (Erzurum, 1992), 277-287, NATO Adv. Sci. Inst. Ser. Math. Phys. Sci., 399 (Kluwer Acad. Publ., Dordrecht, 1993). · Zbl 0822.57017
[4] Kamada, S., Braid and Knot Theory in Dimension Four, 95, (2002), American Mathematical Society · Zbl 0993.57012
[5] Nagase, T.; Hirota, A., The closure of a surface braid represented by a \(4\)-chart with at most one crossing is a ribbon surface, Osaka J. Math., 43, 413-430, (2006) · Zbl 1124.57009
[6] Nagase, T.; Shima, A., On surface braids of index four with at most two crossings, Fundmenta Mathematicae, 188, 167-193, (2005) · Zbl 1088.57017
[7] Nagase, T.; Shima, A., Any chart with at most one crossing is a ribbon chart, Topology Appl., 157, 1703-1720, (2010) · Zbl 1202.57024
[8] Nagase, T.; Shima, A., On charts with two crossings I: There exist no NS-tangles in a minimal chart, J. Math. Sci. Univ. Tokyo, 17, 217-241, (2010) · Zbl 1250.57039
[9] Nagase, T.; Shima, A., On charts with two crossings II, Osaka J. Math., 49, 909-929, (2012) · Zbl 1267.57027
[10] Nagase, T.; Shima, A., Minimal charts, Topology Appl., 241, 291-332, (2018) · Zbl 1394.57020
[11] Nagase, T.; Shima, A., The structure of a minimal \(n\)-chart with two crossings II: Neighborhoods of \(\operatorname{\Gamma}_1 \cup \operatorname{\Gamma}_{n - 1}\), Rev. R. Acad. Cienc. Exactas Fis. Nat. Ser. A. Math. RACSAM, (2018)
[12] K. Tanaka, A note on CI-moves, in Intelligence of Low Dimensional Topology 2006, Ser. Knots Everything, 40, World Sci. Publ., Hackensack, NJ, 2007, eds. J. Scott Carter et al. (2006), pp. 307-314. · Zbl 1136.57014
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.