双圈覆盖问题

Seyntour[1]与Szekeres[5]猜想，每一个无割边的图G具有一个圈集合 使G中的每个边存在于 的两个圈中。本证明此猜想成立当且仅当它对没有非平凡的三个边割的图成立。     

幺半环上模糊有限状态自动机积的覆盖关系

提出了幺半环上模糊有限状态自动机的各种乘积以及覆盖的定义,并得到了一些性质.证明了直积、级联积、圈积三种乘积以及和之间的覆盖关系,得到了乘积自动机、和自动机覆盖关系的一些代数性质.     

若干Mycielski图的点可区别均匀全色数

研究了一些Mycielski图的点可区别均匀全染色(VDETC),利用构造法给出了路、圈、星和扇的Mycielski图的点可区别均匀全色数,验证了它们满足点可区别均匀全染色猜想(VDETCC).     

关于愉快图的Bodendiek猜想

1977年,H.Bodendiek等人提出猜想:一个圈任意加上两个不相邻顶点的边所得的图是愉快图。1980年C.Delorme等人证明了这个猜想,后来,又有一些人不止一次地给出了它的不同方法的证明。本文在变更原猜想条件的情况下,证明了以下定理。     

格值有限状态机的乘积与覆盖

给出了格值有限状态机的覆盖一种新的定义,在这种新的定义下讨论两个格值有限状态机的之间的覆盖关系,也讨论了格值有限状态机全直积、限制直积、级联积与圈积之间的覆盖关系以及格值有限状态机的积与覆盖它们的格值有限状态机的积之间的覆盖关系。     

图的中间图2-pebbling性质和Graham猜想

本文研究了图的2-pebbling性质和Graham猜想.利用图的pebbling数的一些结果,我们研究了路和圈的中间图具有2-pebbling性质,从而也证明了路的中间图满足Graham猜想.     

图的中间图2-pebbling性质和Graham猜想（英文）

本文研究了图的2-pebbling性质和Graham猜想.利用图的pebbling数的一些结果,我们研究了路和圈的中间图具有2-pebbling性质,从而也证明了路的中间图满足Graham猜想.     

图的因子和因子分解的若干进展

本文综述了图的的因子和因子分解近年来的一些新结果。主要有图的因子与各种参数之间的关系,图有某种因子的一些充分必要条件,特别是图有ｋ－因子的一些充分条件以及关于图的因子分解和正交因子分解的一些新结果。文中提出了一些新的问题和猜想。     

图M（Pn）和M（Gn）的点可区别均匀边染色

用构造法研究了路和圈的Mycielski图的点可区别均匀边染色,得到了路和圈的Mycielski图的点可区别均匀边色数,验证了它们满足点可区别均匀边染色猜想（VDEECC）．     

关于3正则图的三匹配交猜想(Ⅱ)

Fan和Raspaud 1994年提出如下猜想：任一无桥3正则图必有三个交为空集的完美匹配．本文证明了如下结果：若G是一个圈4-边连通的无桥3正则图，且存在G的一个完美匹配M1使得G—M1恰为4个奇圈的不交并，则存在图G的两个完美匹配M2和M3使得M1∩M2∩M3=Φ。     

Characterizations of trees with equal paired and double domination numbers

A paired-dominating set of a graph G is a dominating set of vertices whose induced subgraph has a perfect matching, and a double dominating set is a dominating set that dominates every vertex of G at least twice. We show that for trees, the paired-domination number is less than or equal to the double domination number, solving a conjecture of Chellali and Haynes. Then we characterize the trees having equal paired and double domination numbers.     

最后完工机器至多两个空闲的自由作业稠密时间表(英文)

对于自由作业问题,在安排工件时避免不必要空闲所得的时间表称为稠密时间表.稠密时间表的加工总长不超过最优值的2-1/m倍,是一个在机器数m6时尚未被证明的猜想.本文通过引入工件与机器特征函数及机器关于工件非间断等概念,研究当最后完工机器至多有两个空闲区间时,性能比猜想成立的充分条件.     

A proof of Sethares' conjecture

Let (?)(z) be holomorphic in the unit disk △ and meromorphic on △. Suppose / is a Teichmuller mapping with complex dilatation In 1968, Sethares conjectured that f is extremal if and only if either (i)(?) has a double pole or (ii)(?) has no pole of order exceeding two on (?)△. The "if" part of the conjecture had been solved by himself. We will give the affirmative answer to the "only if" part of the conjecture. In addition, a more general criterion for extremality of quasiconformal mappings is constructed in this paper, which generalizes the "if" part of Sethares' conjecture and improves the result by Reich and Shapiro in 1990.     

Some phases of oscillatory integrals

The first example of a phase is presented for which Arhold’s conjecture on the validity of uniform estimates for oscillatory integrals with maximal singularity index is true, while his conjecture on the semicontinuity of the singularity index is false. A rough upper bound for the Milnor number such that the latter conjecture fails is obtained. The corresponding counterexample is simpler than Varchenko’s well-known counterexample to Arnold’s conjecture on the semicontinuity of the singularity index. This gives hope to decrease codimension and the Milnor number for which the conjecture on the semicontinuity of the singularity index fails.     

关于Whitney和Tutte猜想

ｗｈｉｔｎｅｙ和Ｔｕｔｔｅ把平面四色问题化为只与圈上的４染色集有关的问题来研究，从而探讨四色问题的理论证明；提出了一个蕴含着四色定理的猜想。本文研究开集的组合不变性，从而证明Ｗｈｉｔｎｅｙ和Ｔｕｔｔｅ的猜想不成立。     

On the number of pseudo-triangulations of certain point sets

We pose a monotonicity conjecture on the number of pseudo-triangulations of any planar point set, and check it on two prominent families of point sets, namely the so-called double circle and double chain. The latter has asymptotically n¹²nΘ(1) pointed pseudo-triangulations, which lies significantly above the maximum number of triangulations in a planar point set known so far.     

Sparsely intersecting perfect matchings in cubic graphs

In 1971, Fulkerson made a conjecture that every bridgeless cubic graph contains a family of six perfect matchings such that each edge belongs to exactly two of them; equivalently, such that no three of the matchings have an edge in common. In 1994, Fan and Raspaud proposed a weaker conjecture which requires only three perfect matchings with no edge in common. In this paper we discuss these and other related conjectures and make a step towards Fulkerson’s conjecture by proving the following result: Every bridgeless cubic graph which has a 2-factor with at most two odd circuits contains three perfect matchings with no edge in common.     

Pairs of edge disjoint Hamiltonian circuits in 5-connected planar graphs

Summary A variety of examples of 4-connected 4-regular graphs with no pair of disjoint Hamiltonian circuits were constructed in response to Nash-Williams conjecture that every 4-connected 4-regular graph is Hamiltonian and also admits a pair of edge-disjoint Hamiltonian circuits. Nash-Williams's problem is especially interesting for planar graphs since 4-connected planar graphs are Hamiltonian. Examples of 4-connected 4-regular planar graphs in which every pair of Hamiltonian circuits have edges in common are included in the above mentioned examples.B. Grünbaum asked whether 5-connected planar graphs always admit a pair of disjoint Hamiltonian circuits. In this paper we introduce a technique that enables us to construct infinitely many examples of 5-connected planar graphs, 5-regular and non regular, in which every pair of Hamiltonian circuits have edges in common.     

A counterexample to the bipartizing matching conjecture

The bipartizing matching conjecture (BMC) is a rather new approach to the nowhere zero 5-flow conjecture (NZ5FC) and the cycle double cover conjecture (CDCC). We show that the BMC is wrong in its actual version by constructing a counterexample. The construction arises from the investigation of the problem to cover the vertices of a graph by two induced Eulerian subgraphs. Finally, we state a modified version of the BMC which has the same impact on the NZ5FC and CDCC.