Information processing system and method of information processing

An information processing system comprising:

• a trading network obtaining unit configured to obtain a trading network in which a plurality of nodes corresponding one-to-one to a plurality of companies are connected together by an edge indicating a trading relationship;
• a vector obtaining unit configured to select any one of the plurality of nodes as a vector-calculation target node, and to determine, for each of the plurality of nodes, a complex vector by assigning a complex number, the complex vector representing a relationship of the vector-calculation target node with another one of the plurality of nodes, the complex number having a phase corresponding to a distance to the vector-calculation target node, and an absolute value corresponding to an amount of flow going to or coming from the vector-calculation target node;
• a supply chain extracting unit configured to extract a supply chain network in accordance with the complex vector indicating each of the plurality of nodes, the supply chain network being a part of the trading network;
• and
• a tag-transition-diagram generating unit configured to generate a tag transition diagram in accordance with a tag given to nodes included in the supply chain network of the plurality of nodes, the tag transition diagram showing information about the tag in the supply chain network.