本文主要围绕有限CW-复形的分类和不可分解空间压挤乘积的同伦分解这两个同伦论中的基本课题，对Akn-复形，即(n-1)-连通，胞腔维数≤n+k......

For any group G and G-graded ring R with identity,We discuss the relations between graded Von Neumann regularity of grad......

This paper gives a sufficient and necessary condition for twisted products tobe weak Hopf algebras, moreover, gives a de......

...

<正>The Yetter-Drinfeld category of the Hopf algebra over a field is a pre braided category. In this paper we prove this......