Most real-world knowledge graphs, including Wikidata, DBpedia, and Yago are incomplete. Answering queries on such incomplete graphs is an important, but challenging problem. Recently, a number of approaches, including complex query decomposition (CQD), have been proposed to answer complex, multi-hop queries with conjunctions and disjunctions on such graphs. However, all state-of-the-art approaches only consider graphs consisting of entities and relations, neglecting literal values. In this paper, we propose LitCQD -- an approach to answer complex, multi-hop queries where both the query and the knowledge graph can contain numeric literal values: LitCQD can answer queries having numerical answers or having entity answers satisfying numerical constraints. For example, it allows to query (1)~persons living in New York having a certain age, and (2)~the average age of persons living in New York. We evaluate LitCQD on query types with and without literal values. To evaluate LitCQD, we generate complex, multi-hop queries and their expected answers on a version of the FB15k-237 dataset that was extended by literal values.
@article{arxiv.2304.14742,
title = {LitCQD: Multi-Hop Reasoning in Incomplete Knowledge Graphs with Numeric Literals},
author = {Caglar Demir and Michel Wiebesiek and Renzhong Lu and Axel-Cyrille Ngonga Ngomo and Stefan Heindorf},
journal= {arXiv preprint arXiv:2304.14742},
year = {2023}
}