CHEN Guang-ting1,HE Yong2,YAO En-yu2 (1.The School of Science and Arts ,Hangzhou Institute of Electronic Engineering,Hangzhou 310037,China; 2.Department of Mathematics， Zhejiang University, Hangzhou 310027，China)
Abstract：The constrained Steiner minimum tree problem(CSMTP)is presented. Let L be a straight line in a Euclidean plane,and N={A1,A2,…,An} be a set of n points in the same side of L.The problem is to find a point P in L such that the length of Steiner minimum tree about N∪{P} is minimal.In this paper, the cases of n=2 and 3 are solved.
