# Trading relationships When representing a network of clubs as a [graph](https://en.wikipedia.org/wiki/Graph_theory), whether or not an edge connects two members is determined by whether or not they have engaged in a transaction within the [analysis period](/conspoQ5TNmH5pfZqp-LfQ) under consideration. The number of trading relations a club has is referred to as its [degree](https://en.wikipedia.org/wiki/Degree_(graph_theory)). Because trades have a direction (defined [here](/2iRH2t-QRLOYL3cHkbCgTw) by the flow of credit) the graph is [directed](https://en.wikipedia.org/wiki/Directed_graph) and metrics such as [centrality](/lEM9FfewRfqzPpoJWV-MKQ) can be calculated for 'indegree' and 'outdegree' relationships.