摘要： 　给出了内动机下向树中的每一层节点数的计算公式,定出了自动机的图型是圈-树形的充分必要条件。该方法在很多领域有着广泛的应用。

关键词: 自动机, 下向树, 圈-树形

Abstract: A general formula is presented to count the number of nodes in a down-oriented tree. Some necessary and sufficient conditions are presented as well for an autonomous automaton to be a circle tree. This method is appied widely in many fields.

中图分类号: 

• TP301.1