期刊信息
- 刊名： 河北师范大学学报（自然科学版）Journal of Hebei Normal University (Natural Science)
- 主办： 河北师范大学
- ISSN： 1000-5854
- CN： 13-1061/N
- 中国科技核心期刊
- 中国期刊方阵入选期刊
- 中国高校优秀科技期刊
- 华北优秀期刊
- 河北省优秀科技期刊
(K2,3+e)-Design of λKv
摘要/Abstract
λKv 是一个λ重v点完全图, G为一个不带孤立点的简单图.λKv的一个G-设计,常记为(v,G,λ)-GD,是指一个对子 ( X,B),其中X为Kv的点集,B为Kv的一些子图 (亦称为区组 )构成的集合,使得任一区组均与图G同构,且Kv的任意2个不同点组成的边恰在B的λ个区组中出现 .现讨论了2类6点7边图 Gi=K2,3+e(i=1,2)的图设计存在性问题,证明了存在(v,Gi,λ)GD(i=1,2)当且仅当14|λv(v-1),v≥6,且(v,λ)≠(7,1),(8,1).
A left R-moduleR A is called a FCG-projective module in case for each finitely cogenerated moduleRM, A is M-projective. A ring R is said to be a FCGP-ring if each FCG-projective R-module is projective, some equivalent conditions of FCG-projective modules are given, left V-rings and semisimple rings are characterized by FCG-projective modules, characters and equivalent conditions of FCGP-rings are discussed. It is shown that R is a semisimple ring if and only if R is a left V-ring and a FCGP-ring, FCGP-rings are Morita invariant.