1 Introduction
Graphs are ubiquitous in the world and real graphs evolve over time via individual behaviors. For example, social network users establish and/or remove links between each other via the behaviors of following, mentioning, replying, and etc. The user's attributes such as textual features from generated content are also changing. These two types of dynamics, social links and user attributes, have impact on each other. Specifically, on academic co-authorship networks, researchers are looking for collaborators (reflected as neighbor nodes) who have similar or complementary knowledge [1] (which may be reflected as published keywords, a type of node attributes). And their personal research topics may change according to new collaborations. The co-evolutionary patterns of node attributes and graph structure are complex yet valuable, and need to be effectively learned by the model for forecasting future attributes and structures in graph-based applications.