Graph Kernels
Positive Definite Kernels: Past, Present and Future
http://www.math.iit.edu/~fass/PDKernels.pdf
Graph Cartesian Product
http://mathworld.wolfram.com/GraphCartesianProduct.html
Classifications
https://www.csc2.ncsu.edu/faculty/nfsamato/practical-graph-mining-with-R/slides/ppt/Classification.pptx