关于图的E-S不可收缩性的一个结果  

A result on E-S unretractivity of graphs

作　　者：薛自学[1] 

机构地区：[1]甘肃农业大学基础部,兰州730070

出　　处：《甘肃农业大学学报》1999年第3期303-306,共4页Journal of Gansu Agricultural University

摘　　要：推广了Ｋｎａｕｅｒ的结论：ＥｎｄC2n+1[Y]End［Ｙ］＝sEnd到广义字典序积，得到了C2n[Yx|x(C2n+1)]是Ｅ－Ｓ不可收缩的充分必要条件是每个Ｙｘ皆Ｅ－Ｓ不可收缩的。Knauer's conclusion is further discussed in this paper. In the generalized lexicographicproduct, the conclusion End End Y=S End Y is generalized into a newconclusion that the sufficient and necessary condition of being E-S unretrative iseach Yx being E-S unretractive.

关 键 词：广义字典序积 自同态 强自同态 E-S不可收缩性 

分 类 号：O157.5[理学—数学]