A# H^(*rat)是素亚直既约代数的充要条件

THE CONDITIONS OF SUFFICIENCY AND NECESSITY FOR A#H rat BEING SUBDIRECTLY IRREDUCIBLE ALGEBRAS

设Ｈ是Ｈｏｐｆ代数，Ａ是Ｈ余模代数，讨论ＡｃｏＨ，Ａ＃Ｈｒａｔ之间的亚直既约性关系，给出Ａ＃Ｈｒａｔ是素亚直既约代数的一个充要条件．

Let H be a Hopf algebra, A a H comodule algebra, this paper discusses the relations of subdirectly irreducibility between A co H and A#H rat , and gives out a sufficient and necessary condition for A#H rat being a subdirectly irreducible algebra.