摘要
在模范畴中一簇左R-模的余直积即是它们直和,而在中心S-范畴中,余直各表现为零直并.考虑到模范畴与S-系范畴之间的联系,本章首先给出了中心S-系范畴中余直积的一个充要条件,进而利用一般S-系范畴和一元S-系的不交并含零元这一性质,将该充要条件推广到了一般S-系范畴中(定理2.5),成功的给出余直积的一个具体刻画.
Let So - Act be the category of all central S - acts and S - Act the category of all S - acts. Because the forms of coproduct in S - Act and So - Act are different, not all the results which hold in So - Act is also true in general S - Act. In So - Act, we can think of 0 - direct union as the coproduct. This paper gives an equivalent condition for a S - act the coproduct of a family of S - acts. Since the disjoint of a family of S - acts is their coproduct, and the coproduct of any S - act and one element S - act contains zero element, we generalize some results in So - Act to ones in S- Act.
出处
《泰山学院学报》
2008年第3期17-20,共4页
Journal of Taishan University
关键词
S-系
S-同态
零同态
余直积
张量积
S - act
S - morphism
zero morphism
coproduct
tensor product
