Postulates for Provenance: Instance-based provenance for first-order logic

Abstract

Instance-based provenance is an explanation for a query result in the form of a subinstance of the database. We investigate different desiderata one may want to impose on these subinstances. Concretely we consider seven basic postulates for provenance. Six of them relate subinstances to provenance polynomials, three-valued semantics, and Halpern-Pearl causality. Determinism of the provenance mechanism is the seventh basic postulate. Moreover, we consider the postulate of minimality, which can be imposed with respect to any set of basic postulates. Our main technical contribution is an analysis and characterisation of which combinations of postulates are jointly satisfiable. Our main conceptual contribution is an approach to instance-based provenance through three-valued instances, which makes it applicable to first-order logic queries involving negation.