The distance between two separating, reducing slopes is at most 4

沿分离坡道的可约柄添加

Reducible handle additions along separating slopes

本文证明在紧致可定向简单3-流形边界上，若两个分离坡道对应的柄添加均为可约，则它们之间的距离为零，从而在任意边界亏格下验证了Qiu-Zhang猜想中可约-可约情形。

On the Slope of Hyperelliptic Lefschetz Fibrations and the Number of Separating Vanishing Cycles

In this article we find an upper and lower bound for the slope of genus g hyperelliptic Lefschetz fibrations, which is sharp when g = 2, and demonstrate the strong connection, in general, between the slope of hyperelliptic genus g Lefschetz fibrations and the number of separating vanishing cycles. Specifically, we show that the slope is greater than 4-4/g if and only if the fibration contains separating vanishing cycles. We also improve the existing bound on s/n, the ratio of number of separating vanishing cycles to the number of non-separating vanishing cycles, for hyperelliptic Lefschetz fib…

关于3球体中 genus-4 海格劳德面的简化球减少的注记

A note on reducing spheres for the genus-4 Heegaard surface in the 3-sphere

本文提出一个充分条件，用于确定非分离弱减少对被简化球分离的情况，并将简化球复形中的连通性问题转化为证明任意两个顶点在复形中连通的问题。

Dehn fillings of knot manifolds containing essential twice-punctured tori

We show that if a hyperbolic knot manifold $M$ contains an essential twice-punctured torus $F$ with boundary slope $β$ and admits a filling with slope $α$ producing a Seifert fibred space, then the distance between the slopes $α$ and $β$ is less than or equal to $5$ unless $M$ is the exterior of the figure eight knot. The result is sharp; the bound of $5$ can be realized on infinitely many hyperbolic knot manifolds. We also determine distance bounds in the case that the fundamental group of the $α$-filling contains no non-abelian free group. The proofs are divided into the four cases $F$ is a …

Boundary reducible handle additions on simple 3-manifolds

Let $M$ be a simple manifold, and $F$ be a component of $\partial M$ of genus two. For a slope $γ$ on $F$, we denote by $M(γ)$ the manifold obtained by attaching a 2-handle to $M$ along a regular neighborhood of $γ$ on $F$. In this paper, we shall prove that there is at most one separating slope $γ$ on $F$ so that $M(γ)$ is $\partial$-reducible.

Toroidal and Boundary-Reducing Dehn Fillings

Let M be a simple 3-manifold with a toral boundary component partial_0 M. If Dehn filling M along partial_0 M one way produces a toroidal manifold and Dehn filling M along partial_0 M another way produces a boundary-reducible manifold, then we show that the absolute value of the intersection number on partial_0 M of the two filling slopes is at most two. In the special case that the boundary-reducing filling is actually a solid torus and the intersection number between the filling slopes is two, more is said to describe the toroidal filling.