##
**Multiple genus 2 Heegaard splittings: a missed case.**
*(English)*
Zbl 1232.57020

It was shown independently in [M. Boileau and J.-P. Otal, C. R. Acad. Sci., Paris, Sér. I 303, 19–22 (1986; Zbl 0596.57010)] and [C. Hodgson and J. H. Rubinstein, in: Knot theory and manifolds, Proc. Conf., Vancouver/Can. 1983, Lect. Notes Math. 1144, 60–96 (1985;Zbl 0605.57022)] that any two genus-one Heegaard decompositions of a given 3-manifold are isotopic. In contrast, some Seifert manifolds have distinct genus-two Heegaard splittings. In [Geom. Topol. Monogr. 2, 489–553 (1999; Zbl 0962.57013)], H. Rubinstein and M. Scharlemann gave a near-complete list of ways in which multiple splittings could be constructed.

In the paper reviewed here, the authors fill a gap in this earlier work by describing a final class of examples omitted from the list of Rubinstein and Scharlemann. The examples have some interesting new properties not shared by the examples in Rubinstein and Scharlemann’s paper. In particular, at least some of the new examples are of Hempel distance 3, whereas all of the examples in the original work were of Hempel distance 2.

In the paper reviewed here, the authors fill a gap in this earlier work by describing a final class of examples omitted from the list of Rubinstein and Scharlemann. The examples have some interesting new properties not shared by the examples in Rubinstein and Scharlemann’s paper. In particular, at least some of the new examples are of Hempel distance 3, whereas all of the examples in the original work were of Hempel distance 2.

Reviewer: Cynthia L. Curtis (Ewing)

### MSC:

57N10 | Topology of general \(3\)-manifolds (MSC2010) |

57M15 | Relations of low-dimensional topology with graph theory |

PDFBibTeX
XMLCite

\textit{J. Berge} and \textit{M. Scharlemann}, Algebr. Geom. Topol. 11, No. 3, 1781--1792 (2011; Zbl 1232.57020)

### References:

[1] | J Berge, A classification of pairs of disjoint nonparallel primitives in the boundary of a genus two handlebody |

[2] | J Berge, A closed orientable 3-manifold with distinct distance three genus two Heegaard splittings, to appear |

[3] | J Hempel, 3-manifolds as viewed from the curve complex, Topology 40 (2001) 631 · Zbl 0985.57014 |

[4] | Y N Minsky, The classification of punctured-torus groups, Ann. of Math. \((2)\) 149 (1999) 559 · Zbl 0939.30034 |

[5] | H Rubinstein, M Scharlemann, Genus two Heegaard splittings of orientable three-manifolds, Geom. Topol. Monogr. 2, Geom. Topol. Publ., Coventry (1999) 489 · Zbl 0962.57013 |

[6] | M Scharlemann, Berge’s distance 3 pairs of genus 2 Heegaard splittings · Zbl 1226.57033 |

[7] | M Scharlemann, Genus two Heegaard splittings: an omission, Geom. Topol. Monogr. 2, Geom. Topol. Publ., Coventry (1999) 577 · Zbl 0962.57013 |

[8] | M Scharlemann, A Thompson, Heegaard splittings of \((\mathrm{surface})\times I\) are standard, Math. Ann. 295 (1993) 549 · Zbl 0814.57010 |

[9] | A Thompson, The disjoint curve property and genus 2 manifolds, Topology Appl. 97 (1999) 273 · Zbl 0935.57022 |

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.