摘 要
近年来﹐半群代数理论在计算机科学中得到了广泛的应用﹐引起人们的高度重视﹐并成为数学家和计算机科学家深入研究的对象﹐有了迅速的发展。
关键字：字；半群；自由半群；长度
ABSTRACT
In recent years, the theories of the semigroup have been applied extensively in computer technology,taking people’s hi-
gh attention ,and have been studied deeply by the mathmatists and computer scientists ,and have developed rapidly.
Free semigroup is a very important branch of the semigroup.With the development of science technology, free semigroup takes a very important role in machine, automate, automatic operation, language,and code . This text discusses that only has trivial solves under the conditrion that m,n,p 2.The word is a core unit in free semigroup. According to the words length of a and c,the text is spanided three parts:|a|>|c|, |a|=|c |, |a|<|c|,and discusses eight kinds of circumstances.
Key words；word; semigroup; free semigroup; length
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