First-order queries on classes of structures with bounded expansion

Wojciech Kazana (1) , Luc Segoufin (2)

1 ENS Cachan - École normale supérieure - Cachan
2 VALDA - Value from Data

We consider the evaluation of first-order queries over classes of databases with bounded expansion. The notion of bounded expansion is fairly broad and generalizes bounded degree, bounded treewidth and exclusion of at least one minor. It was known that over a class of databases with bounded expansion, first-order sentences could be evaluated in time linear in the size of the database. We give a different proof of this result. Moreover, we show that answers to first-order queries can be enumerated with constant delay after a linear time preprocessing. We also show that counting the number of answers to a query can be done in time linear in the size of the database.

Mots clés: Enumeration; First-order; Constant delay; Bounded expansion

Domaines: Informatique et langage [cs.CL]

Wojciech Kazana, Luc Segoufin. First-order queries on classes of structures with bounded expansion. Logical Methods in Computer Science, 2020, 16 (1), ⟨10.23638/LMCS-16(1:25)2020⟩. ⟨hal-01706665v2⟩