Directed scale-free graphs
We introduce a model for directed scale-free graphs that grow with preferential attachment depending in a natural way on the in- and out-degrees. We show that the resulting in- and out-degree distributions are power laws with different exponents, reproducing observed properties of the world-wide web. We also derive exponents for the distribution of in- (out-) degrees among vertices with fixed out- (in-) degree. We conclude by suggesting a corresponding model with hidden variables.
Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms
Bollobás, B., Borgs, C., Chayes, J., & Riordan, O. (2003). Directed scale-free graphs. Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms, 132-139. Retrieved from https://digitalcommons.memphis.edu/facpubs/4534