# Conservative Extensions for Existential Rules

arXiv: https://arxiv.org/abs/2202.05689 · HTML: https://mlsanity.com/paper/2202.05689/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Builds on 6 of its 36 references that are in the map.
- First posted on arXiv 11 Feb 2022.

## Builds on (most cited first, 6 of 6)

- [The DL-Lite Family and Relations](https://mlsanity.com/paper/1401.3487/) (2014)
- [Ontology-based Data Access: A Study through Disjunctive Datalog, CSP, and MMSNP](https://mlsanity.com/paper/1301.6479/) (2013)
- [Inseparability and Conservative Extensions of Description Logic Ontologies: A Survey](https://mlsanity.com/paper/1804.07805/) (2018)
- [Conservative Extensions in Horn Description Logics with Inverse Roles](https://mlsanity.com/paper/2011.09858/) (2020)
- [Conservative Extensions in Guarded and Two-Variable Fragments](https://mlsanity.com/paper/1705.10115/) (2017)
- [Query Inseparability for ALC Ontologies](https://mlsanity.com/paper/1902.00014/) (2019)

## Abstract (arXiv)

We study the problem to decide, given sets T1,T2 of tuple-generating dependencies (TGDs), also called existential rules, whether T2 is a conservative extension of T1. We consider two natural notions of conservative extension, one pertaining to answers to conjunctive queries over databases and one to homomorphisms between chased databases. Our main results are that these problems are undecidable for linear TGDs, undecidable for guarded TGDs even when T1 is empty, and decidable for frontier-one TGDs.