自由半群上的完全同余关系

Perfect congruences on a free semigruop

本文利用字母集X上的等价关系刻划了自由半群X^+的完全同余关系。证明了完全同余关系的特征性质:商半群是自由半群。最后,给出了亚群X~*上同余关系完全性的几个等价条件。

This paper discribes perfect congruences on a free semigruop using equivalence rela- tions on an alphbet set X. It also proves that a congruence on X^+ is perfect if and only if the quotient is free. Finally some equivalent conditions of a perfect congruence on X are given.