Predictive temporal embedding of dynamic graphs

In recent years, substantial effort has been devoted to learning to represent the static graphs and their substructures. A few studies explored utilizing temporal information available in a dynamic setting in order to address the node representation learning. However, the representation learning problem for the entire graph in a dynamic context is yet to be addressed. In this paper, we propose an unsupervised encoder-decoder framework that projects a dynamic graph at each time step into a d-dimensional space, taking into account both the graph's topology and dynamics. We investigate two different strategies. First, we address the representation learning problem by auto-encoding the graph dynamics. Second, we formulate a graph prediction problem and enforce the encoder to learn the representation that an autoregressive decoder then uses to predict the future of a dynamic graph. Gated graph neural networks (GGNNs) are incorporated to learn the topology of the graph at each time step and Long short-term memory networks (LSTMs) are leveraged to propagate the temporal information among the nodes through time. We demonstrate the efficacy of our approach with a graph classification task using two real-world datasets of animal behaviour and brain networks.