S3Former: Sequential, Structural, and Statistical Fusion for Continuous-Time Dynamic Graphs

Continuous-time dynamic graphs model evolving systems with irregularly timed interactions, where predicting future links requires reasoning over temporal evolution, local topology, and historical relation patterns. Existing memory-based and sequence-based methods capture temporal dependencies effectively, but they often organize historical interactions as node memories or serialized neighbor sequences. As a result, they lack explicit analysis of the interaction structure around candidate nodes which prevents them from explicitly modeling local topological patterns of candidate nodes at inference time. They also lack explicit causal statistical memory for activity, recency, and repeated pairwise interactions. Motivated by these drawbacks, we propose S3Former, a temporal graph framework that jointly models sequential dynamics, shared pair-centered structure, and online statistical memory. For each candidate interaction, S3Former encodes long-term and short-term historical sequences, constructs a history-induced shared pair subgraph around the two endpoints, and computes node-level and pair-level statistics from past events only. A two-level context-aware fusion mechanism further combines these signals: NodeCCF learns reliable endpoint representations, while PairCCF performs candidate-specific relation correction using explicit pair memory. Experiments on 10 dynamic graph benchmarks show that S3Former achieves state-of-the-art performance on most datasets in both transductive and inductive link prediction. Ablation studies confirm the effectiveness of shared pair-subgraph modeling, online statistical memory, and hierarchical fusion.