Bandt-Wang的一个定理的新证明

讨论格自仿Tile的边界结构,得到平面格自仿Tile的边界为简单闭曲线的一个充分条件;作为应用,给出Bandt-Wang的一个定理的新证明.     

单形构造定理的一种代数证法

给出n维欧氏空间En中n维单形构造定理的一种代数证法,这种代数证法十分简洁.     

关于Shimoji and Takahashi一个定理的简单证明

目的是在一般Banach空间中建立一个无限可数多个非扩张映像族的公共不动点的强收敛定理．使用一些新的分析技巧,尤其是Dotson引理和W映像技巧,给出了Shimoji and Takahashi的一个定理的简单证明．     

A Proof of Sharkovsky's Theorem

This paper presents a variation on the standard directed graph proof. This variation makes use of the natural representation of the symmetric group given by one-dimensional maps.     

A Geometrical Proof of Shiota's Theorem on a Conjecture of S. P. Novikov

We give a new proof of Shiota's theorem on Novikov's consecture, which states that the K.P. equation characters Jacobians among all indecomposable principally polarized abelian varieties.     

A morphism of intersection homology induced by an algebraic map

Let be a map of algebraic varieties. Barthel, Brasselet, Fieseler, Gabber and Kaup have shown that there exists a homomorphism of intersection homology groups compatible with the induced homomorphism on cohomology. The crucial point in the argument is reduction to the finite characteristic. We give an alternative and short proof of the existence of a homomorphism . Our construction is an easy application of the Decomposition Theorem.

     

整数偶序列为蕴含强连通的Beineke－Harary判准

一个由ｎ个非负整数有序对构造的序列是有向可图的,如果它是某个有向图的度序列．一个有向可图序列是蕴含强连通的,如果它是某个强连通有向图的度序列．Ｂｅｉｎｅｋｅ和Ｈａｒａｒｙ给出了一个有向可图序列为蕴含强连通的判准．Ｂｅｉｎｅｋｅ－Ｈａｒａｒｙ判准的充分性证明是“相当长”的（见［１］）．本文的目的是给出Ｂｅｉｎｅｋｅ－Ｈａｒａｒｙ判准的充分性的一个简短证明．     

A Combinatorial Proof of Rohlin Theorem

We present an algorithmic and combinatorial proof of the following well-known theorem, originally proved by Rohlin: Every closed orientable 3-manifold M³ bounds a simply connected orientable 4-manifold M⁴. More precisely, an edge-coloured graph representing M⁴ is obtained as the final result of a finite and well-determined sequence of admissible moves, starting from any given edge-coloured graph representing M³.     

A New Proof of Bartholdi's Theorem

We give a new proof of Bartholdi's theorem for the Bartholdi zeta function of a graph. Supported by Grant-in-Aid for Science Research (C)     

A New Proof of Calabi-Yau＇s Theorem

We give a new proof of Calabi-Yau＇s theorem on the volume growth of Riemannian manifolds with non-negative Ricci curvature.     

Cayley-Hamilton定理的一个证明

从Vandermonde行列式出发,给出了Cayley-Hamilton定理的一个新的证明,也给出了有限维向量空间的一些结论的新的证明.     

A Constructive Proof of Beurling-Lax Theorem

This paper deals with an alternative proof of Beurling-Lax theorem by adopting a constructive approach instead of the isomorphism technique which was used in the original proof.     

A New Proof of Calabi-Yau's Theorem

We give a new proof of Calabi-Yau's theorem on the volume growth of Rie- mannian manifolds with non-negative Ricci curvature.     

矩阵秩分解定理的一个证明及其应用

矩阵的秩分解定理是矩阵论中的一个基础性定理.本文给出了秩分解定理的一个证明,描述了其中可逆矩阵P,Q的构造,讨论了秩分解定理及其P,Q的构造在解线性方程组中的应用,以及在判别Sylvester不等式等号成立中的应用.     

A short proof of a theorem on degree sets of graphs

For a finite simple graph G, we denote the set of degrees of its vertices, known as its degree set, by D(G). Kapoor, Polimeni and Wall [Degree sets for graphs, Fund. Math. 95 (1977) 189-194] have determined the least number of vertices among graphs with a given degree set. We give a very short proof of this result.     

Coven和Hedlund一个定理的较简单的证明

Coven和Hedlund在[1]中证明：若区间映射的周期集为有限集,则它的每一个非游荡点都是周期点。本给出了这一定理的一个较简单的证明。此外,我们还用“同伦”的方法简化了该的一个关键引理的证明。     

柯西积分定理的一个新证明

我们利用调和分析的方法给出了柯西积分定理的一个新的证明,我们的证明比古莎所给出的证明简单.