Zero-shot Logical Query Reasoning on any Knowledge Graph

Zero-shot Logical Query Reasoning on Any Knowledge Graph

Introduction to UltraQuery: A Paradigm Shift in Knowledge Graph Reasoning

Knowledge Graphs (KGs) are pivotal in a myriad of applications, from question answering systems to semantic web services, owing to their structured representation of knowledge. Complex Logical Query Answering (CLQA) extends the utility of KGs by enabling the resolution of intricate queries composed of multiple logical operations and projections. However, the static nature of existing approaches, which rely on pre-learned embeddings specific to given entity or relation vocabularies, severely limits their applicability to novel KGs without substantial retraining. This paper introduces UltraQuery, a novel inductive reasoning model capable of zero-shot logical query reasoning on any KG, effectively addressing the adaptability challenge that plagues current CLQA systems.

Theoretical Background and Related Works

Extant CLQA techniques are predominantly transductive, tailored to specific entity-relation vocabularies within training graphs, thereby undermining their utility on unseen graphs. Few attempts towards inductive generalization exist but are constrained by fixed relation vocabularies, failing to extend to KGs with entirely novel entities and relations. In contrast, UltraQuery stands as the first model to tackle the inductive $(e,r)$ scenario, where both entities and relations are unfamiliar at inference time, through innovative employment of transferable meta-graph representations and fuzzy logic for logical operations, circumventing the need for external node or edge features.

Methodological Advancements: The UltraQuery Approach

UltraQuery's innovative architecture is grounded on two core components:

1. Inductive Relation Projection: Leveraging Ultra, a pre-trained inductive KG reasoning model, UltraQuery dynamically constructs relation representations from a meta-graph of relation interactions, enabling the model to generalize across different KGs irrespective of their specific vocabularies.
2. Inductive Logical Operations: Utilizing non-parametric fuzzy logics, UltraQuery effectively models logical operations (conjunction, disjunction, negation) across fuzzy sets, facilitating adaptable and scalable reasoning over any KG.

This architecture enables UltraQuery to reliably perform CLQA on entirely new KGs, showcasing remarkable zero-shot inference capabilities across 23 diverse datasets, and outperforming existing baselines in 14 of those in terms of both Mean Reciprocal Rank (MRR) and Hits@10 metrics for complex query answering.

Experimental Insights and Practical Implications

Experimental evaluations underscore UltraQuery's superior performance, particularly in the most challenging inductive $(e,r)$ scenarios, suggesting a significant leap towards KG-agnostic complex query answering systems. This development not only advances the frontier of KG reasoning but also encourages the adoption of KGs in domains where rapid adaptability to novel knowledge structures is crucial. Moreover, the dual benefits of reducing computational expense and environmental impact, by negating the need for extensive retraining on new datasets, further amplify UltraQuery's utility in real-world applications.

Future Directions and Conclusion

While UltraQuery pioneers in adapting to new KGs without retraining, future explorations might delve into refining the methodology to mitigate challenges like the multi-source propagation issue and exploring the incorporation of temporal dynamics or numerical literals into the CLQA framework. The innovative stride made by UltraQuery in enabling zero-shot logical reasoning on any KG opens new avenues for research and applications, promising a more versatile and responsive landscape for KG-driven technologies.