说明：  图论〔Graph Theory〕是数学的一个分支。它以图为研究对象。图论中的图是由若干给定的点及连接两点的线所构成的图形，这种图形通常用来描述某些事物之间的某种特定关系，用点代表事物，用连接两点的线表示相应两个事物间具有这种关系。
(Graph theory [Graph Theory] is a branch of mathematics. Pictured research object. Graph theory is constituted by a number of the given point and a line connecting the two points of the graph, this graph is generally used to describe a particular relationship between certain things represent things, with the point connecting the two points The line represents this relationship between the corresponding two things.)