Many query languages for graph-structured data are based on regular path expressions, which describe relations among pairs of nodes. We propose an extension that allows to retrieve groups of nodes based on group structural characteristics and relations to other nodes or groups. It allows to express group selection queries in a concise and natural style, and can be integrated into any query language based on regular path queries. We present an efficient algorithm for evaluating group queries in polynomial time from an input data graph. Evaluations using real-world social networks demonstrate the practical feasibility of our approach.
['Vitaliy Liptchinsky', 'Benjamin Satzger', 'Rostyslav Zabolotnyi', 'Schahram Dustdar']
Expressive languages for selecting groups from graph-structured data