The arithmetic numberings of circular graphs C2n(1,n) have been given. It has been proven that cir cular graphs C2n+1 (1, 2) and C2n+1 (1,n) are not arithmetic graphs.

• 给出循环图C2n（1，n）的算术标号，证明了循环图C2n＋1（1，2）和C2n＋1（1，n）不是算术图。