Nov. 29, 2022, 11:11 a.m.

Anthony W. Lin from the University of Kaiserslautern will be our guest at the Institute of Computer Science from December, 5 to December 9. The visit will take place as a part of visiting professors' arrival program (IDUB).

He will give a talk on Data Path Queries over Embedded Graph Databases on Tuesday, December 6 at 12:15 pm in Room 25.


We initiate the study of data-path query languages (in particular, regular data path queries (RDPQ) and conjunctive RDPQ (CRDPQ)) in the classic setting of embedded finite model theory, wherein each graph is "embedded" into a background infinite structure (with a decidable FO theory or fragments thereof). Our goal is to address the current lack of support for typed attribute data (e.g. integer arithmetics) in existing data-path query languages, which are crucial in practice. We propose an extension of register automata by allowing powerful constraints over the theory and the database as guards, and having two types of registers: registers that can store values from the active domain, and read-only registers that can store arbitrary values. We prove NL data complexity for (C)RDPQ over the Presburger arithmetic, the real-closed field, the existential theory of automatic structures and word equations with regular constraints. All these results strictly extend the known NL data complexity of RDPQ with only equality comparisons, and provides an
answer to a recent open problem posed by Libkin et al. Among others, we introduce one crucial proof technique for obtaining NL data complexity for data path queries over embedded graph databases called "Restricted Register Collapse (RRC)", inspired by the notion of Restricted Quantifier Collapse (RQC) in embedded finite model theory.