数学物理学报 ›› 2000, Vol. 20 ›› Issue (4): 493-498.
(1中国科学院理论物理研究所,
2河南大学数学系,
3中国科学院应用数学所与高科中心
4中山大学数学系)
2 Department of Mathematics, Henan University, Kaifeng 475001,P.R.China,
3 CCAST and Institute of Applied Mathematics, Academia Sinica, Beijiang 100080,P.R.China,
4 Department of Mathematics,Zhongshan University,Guangzhou 510275,P.R.China)