Background Graph Mining Origin of Graph Theory: Seven Bridges of Konigsberg(proposed by Leonhard Euler()) --wiki The city of Konigsberg in Prussia(now Kaliningrad,Russia)was set on both sides of the Pregel River,and included two large islands which were connected to each other,or to the two mainland portions of the city,by seven bridges.The problem was to devise a walk through the city that would cross each of those bridges once and only once.Origin of Graph Theory: Seven Bridges of Königsberg (proposed by Leonhard Euler(欧拉)) The city of Königsberg in Prussia (now Kaliningrad, Russia) was set on both sides of the Pregel River, and included two large islands which were connected to each other, or to the two mainland portions of the city, by seven bridges. The problem was to devise a walk through the city that would cross each of those bridges once and only once. --wiki Background Graph Mining