科研之友
微信
新浪微博
Facebook
分享链接
摘要
An endomorphism of the free monoid is invertible if it is injective and extends to an automorphism of the free group generated by . A simple example: the endomorphism that leaves all generators invariant except one, say a, which is mapped to ba for some other generator b. We give a monoid presentation for the submonoid generated by all such endomorphisms when a and b are taken arbitrarily. These left translations are a special case of Nielsen positive transformations: "left" because the mutiplicative constant acts on the left and "positive" because this constant belongs to the free monoid, not the free group.
- 出版日期2016-12
