子群为Abel群的纯整群并

Orthogroups of Which Every Subgroup Is Abelian

解决了簇ＯＨＡ的字的问题，即找出一个算法来判定一个恒等式ｓ＝ｔ是否对簇ＯＨＡ中所有的半群都成立．作为簇ＯＨＡ的字的问题的解的一个应用，我们得到：一个正则半群Ｓ是子群为Ａｂｅｌ群的纯整群并当且仅当对任意的ａ，ｂ∈Ｓ，有Ｖ（ａｂ）＝Ｖ（ｂａ）．

The word problem of the variety OHA is solved, i.e., an algorithm which decides whether an identity s=t holds in all semigroups of OHA or not is given. As an application, the following result is obtained:For a regular semigroup S, S is an orthogroup of which every subgroup is abelian if and only if for any a,b in S, V(ab)=V(ba).