TG-GAN: Continuous-time Temporal Graph Deep Generative Models with Time-Validity Constraints

Deep generative models of graph-structured data have become popular in very recent years. Although initial research has focused on static graphs in applications such as molecular design and social networks, many challenges involve temporal graphs whose topology and attribute values evolve dynamically over time. Sophisticated and unknown network processes that affect temporal graphs cannot be captured adequately by prescribed models. Application areas include social mobility networks and catastrophic cybersecurity failures. These web-scale applications challenge current deep graph generative models with the need to capture 1) time-validity constraints, 2) time and topological distributions, and 3) joint time and graph encoding and decoding. Here, we propose the “Temporal Graph Generative Adversarial Network” (TG-GAN) for continuous-time graph generation with time-validity constraints 1. TG-GAN can jointly generate the time, node, and edge information for truncated temporal walks via a novel recurrent-based model and a valid time decoder. The generated truncated temporal walks are then assembled into time-budgeted temporal walks for temporal graphs under the learned topological and temporal dependencies. In addition, a discriminator is proposed to combine time and node encoding operations over a recurrent architecture to distinguish generated sequences from real ones sampled by a truncated temporal walk sampler. Extensive experiments on both synthetic and real-world datasets confirm that TG-GAN significantly outperforms five benchmarking methods in terms of efficiency and effectiveness.