引入了可换群的稠密子群，并研究了它的基本性质。
Basic properties of the dense sub-semigroups in commutative groups are studied.
对有限可换半群进行了讨论，建立了有限可换半群与有限可换群之间的关系。
This paper has made some discussions on the finite commutative semigroup. The relationship between the finite commutative semigroup and the finite commutative group is established.
本文主要对几乎可换环上酉群的基本子群的正规性进行了研究。
This thesis mainly works on the normality of elementary subgroup of Unitary group over almost commutative rings.
本文主要对几乎可换环上酉群的基本子群的正规性进行了研究。
This thesis mainly works on the normality of elementary subgroup of Unitary group over almost commutative rings.
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