（P，1）同态及其应用

(P, 1 ) HOMOMORPHISM AND ITS APPLICATIONS

本文定义了ｎ级到ｎ－１级的Ｐ元ｄｅＢｒｕｉｊｎ－Ｇｏｏｄ图之间的（Ｐ，１）同态，并利用给出了一个圈为自对偶圈的判断条件，以及自对偶圈的结构定理．

In this paper,we define a (P, 1 ) homomorphism form p-arg de Bruijn-Good graph of n-stage to one of (n-1 )-stage. By using it,we give a necessary and sufficient condition of which a cyCle is a self-dual cycle,and we also present a structure theorem of self-dual cycled.