高亏格膜泡形状的数值计算

通过对Willmore区域外,特别是中等及较小约化体积下的形状及其演化进行深入细致的研究,发现在这一区域的形状要远比原有的猜测丰富,亏格g=2的膜泡会展现出比已有结果更多迷人的形状并出现新的膜泡相变分支.同时,数值计算的结果更加期待实验验证,从而为曲率模型的正确性提供有力支持.     

Knots of genus one or on the number of alternating knots of given genus

We prove that any non-hyperbolic genus one knot except the trefoil does not have a minimal canonical Seifert surface and that there are only polynomially many in the crossing number positive knots of given genus or given unknotting number.

     

A generalization of curve genus for ample vector bundles. I

A new genus g = g (X, ?) is defined for the pairs (X, ?S)that consist of n-dimensional compact complex manifolds X and ample vector bundles ? of rank r less than n on X. In case r = n-1g is equal to curve genus. Above pairs (X,?) with g less than two are classified. For spanned ? it is shown that g is greater than or equal to the irregularity of X, and its equality condition is given.     

A slice genus lower bound from Khovanov–Rozansky homology

We show that a generic perturbation of the doubly-graded Khovanov–Rozansky knot homology gives rise to a lower-bound on the slice genus of a knot. We prove a theorem about obtainable presentations of surfaces embedded in 4-space, which we use to simplify significantly our algebraic computations.     

循环图C(2n,2)(n＞2)在射影平面上的嵌入计数

图在球面上的嵌入个数即柔性问题已经由刘彦佩教授解决,研究图在射影平面上的嵌入亦有着重要的意义。本文利用刘彦佩教授创建的嵌入联树模型得出了循环图C(2n,2)(n>2)在射影平面上的嵌入个数。     

一类Dirichlet问题的多解存在性

利用H_0^1（Ω）空间分解以及亏格和形变引理给出了半线性椭圆方程-△=g（x,μ）的Dirichlet问题无穷多解的存在性定理．     

Heegaard Genus Formula for Haken Manifolds

Suppose M is a compact orientable 3-manifold and a properly embedded orientable boundary incompressible essential surface. Denote the completions of the components of M – Q with respect to the path metric by M ¹, ...,M ^k . Denote the smallest possible genus of a Heegaard splitting of M, or M ^j respectively, for which ∂M, or ∂M ^j respectively, is contained in one compression body by g(M, ∂M), or g(M ^j , ∂M ^j ) respectively. Denote the maximal number of non-parallel essential annuli that can be simultaneously embedded in M ^j by n _j . Then

关于图的余树的奇连通分支数的内插定理

本文研究了连通图的余树的奇连通分支数与其可定向嵌入的关系.我们先给出了关于连通图的余树的奇连通分支数的内插定理.作为其应用,我们推广了Xuong和刘彦佩关于图的最大亏格的计算公式,并且证明了如下结果:任意一个连通图G一定满足下列条件之一: (a)对于任意的满足γ(G)≤g≤γM(G)整数g,只要图G嵌入到可定向曲面Sg上,就存在支撑树T,使g-1/2β(G)-ω(T)),其中,γ(G)与γM(G)分别是图G的最小和最大亏格,β(G)与ω(T)分别是图G的Betti数和由T确定的余树的奇连通分支数; (b)对连通图G的任意一个支撑树T,G可以嵌入某个可定向曲面上使其恰好有ω(T) 1个面.特别地,我们给出了所有非平面的3-正则的Hamilton图G所嵌入的可定向曲面的亏格的计算公式.     

Incompressible Surfaces in Handlebodies and Closed 3-manifolds

in this paper we prove that for any positive integer n, 1) a handlebody of genus 2contains a separating incompressible surface of genus n, and 2) there exists a closed 3manifold of heegaard genus 2 which contains a separating incompressible surface of genus n.