一些图的星着色数(英文)

由A .Vince定义的星着色数推广了一般的着色数的定义 .关于星着色数 ,给出一些有用的结果 ,并且得到了满足 χ(G) =χ (G)

Sierpiński Gasket图的星着色

研究了Sierpiński gasket图Sn的星着色,证明了在同构意义下S3是唯一的4-星可着色的,且给出了Sierpiński gasket图Sn的星色数的精确值为χs(Sn)=5(n≥4).

图的k-星着色的Grbner基求解

对于具有n个顶点的简单连通图G,首先证明求解G的k-星着色等价于一个多元多项式方程组在{1,2,…,k}上的求解问题,其次使用Grbner基给出求解该多元多项式方程组的方法,从而得到求G的星色数的一个可行途径,最后通过实例验证了此代数计算方法的有效性.

关于(k,d)─图的性质

（ｋ，ｄ）－图是Ａ，Ｖｉｎｃｅ在１９８８年研究图的星着色时给出的定义．（ｋ，ｄ）－图在研究图的星着色中起着非常重要的作用．本文给出了一些（ｋ，ｄ）－图的，＆质，并根据这些性质构造了一个４－正则，４－连通的平面图，其星色数为４．

Role of iron in hepatic fibrosis: One piece in the puzzle

Iron is an essential element involved in various biological pathways. When present in excess within the cell, iron can be toxic due to its ability to catalyse the formation of damaging radicals, which promote cellular injury and cell death. Within the liver, iron related oxidative stress can lead to fibrosis and ultimately to cirrhosis. Here we review the role of excessive iron in the pathologies associated with various chronic diseases of the liver. We also describe the molecular mechanism by which iron contributes to the development of hepatic fibrosis.