Graph contrastive learning (GCL) emerges as the most representative approach for graph representation learning, which leverages the principle of maximizing mutual information (InfoMax) to learn node representations applied in downstream tasks. To explore better generalization from GCL to downstream tasks, previous methods heuristically define data augmentation or pretext tasks. However, the generalization ability of GCL and its theoretical principle are still less reported. In this paper, we first propose a metric named GCL-GE for GCL generalization ability. Considering the intractability of the metric due to the agnostic downstream task, we theoretically prove a mutual information upper bound for it from an information-theoretic perspective. Guided by the bound, we design a GCL framework named InfoAdv with enhanced generalization ability, which jointly optimizes the generalization metric and InfoMax to strike the right balance between pretext task fitting and the generalization ability on downstream tasks. We empirically validate our theoretical findings on a number of representative benchmarks, and experimental results demonstrate that our model achieves state-of-the-art performance.

本文提出了一个名为 GCL-GE 的指标来衡量图对比学习GCL的一般化能力，并通过信息理论的角度理论上证明了一个互信息的上界。基于这个证明，我们设计了一个名为InfoAdv的GCL框架，该框架具有增强的一般化能力，在预训练任务适配和下游任务的一般化能力之间取得了平衡，并在各种基准测试中取得了最先进的性能。

基于信息论的通用图形对比学习