Gray nodes in complex network and the degree of grayness

Based on the theories of complex network and gray system, the conclusion is proposed that there are gray nodes in the complex network with two styles: gray nodes(I) and gray nodes(II). The first one is the existent unknown gray nodes, and the other is the evolution gray nodes, which are designed the relevant definitions. Furthermore, given the description of complex network, grayness degree can be divided into two forms—the relative grayness degree (RGD) and the absolute grayness degree (AGD).