Address：Department of Mathematics,

                  National Taiwan Normal University ,

                  88,Sec. 4, Ting Chou Road,Taipei,116,

                  Taiwan, R.O.C.

        Tel：+ 886-2-7734-6627

                  + 886-2-29323430

       Fax：+ 886-2-29332342

  E-mail：min@math.ntnu.edu.tw