在图形中若于个边(edge)上加上一些值，此数值称为比重( weight ) 。而此图形称为比重图形(Weight Graph ) ，若weight是成本( cost )或距离( distance ) ，则称此图形为网路( Network )。根据Spanning Tree的定义，知一个图形可有许多不同spanning tree ，在network中找出一个具有最小成本( Cost )的Spanning tree ，则此Spanning tree称为最小成本生成树。-If in the graph in a side (edge) to add some value, this value as the proportion (weight). This graph is called the proportion of graphics (Weight Graph), if the weight is the cost (cost) or distance (distance), said the graphics for the network (Network). Spanning Tree in accordance with the definition of a graph to know there are many different spanning tree, in the network to find a minimum cost (Cost) of the Spanning tree, then the minimum cost Spanning tree known as the spanning tree.