研究了无限亚循环群的自同构,得到了它们的自同构群,并且证明了下面的定理:无限亚循环群G的自同构都是内自同构当且仅当G同构于下列群之一:(i)ZξZ^p),其中p为奇素数,l为正整数,ξ把Z的生成元1变为ξ(1)=m时,p m,并且Aut Z(pl)=Z^pl*=Z(pl-1)(p-1))=〈m〉;(ii)无限二面体群D∞.
We discuss automorphisms of infinite metacyclic groups and present their automorphism groups,and then we prove the following result:All automorphisms of an infinite metacyclic group G are inner automorphisms if and only if G is isomorphism to one of following groups:(i) Z ξZp^l,where p is an odd prime,l is an integer,ξmaps the generator 1 of Z toξ(1)=m,p m,and Aut Zp-l=Zp^l*=Z(p^(1-1)(p-1))=〈m〉; (ii) The infinite dihedral group D∞.