Someone slept in my bed! On the entailment problem for conjunctive queries with safe negation over DL-Lite$_{core}$ knowledge bases

Jerzy Marcinkowski; Piotr Ostropolski-Nalewaja

Someone slept in my bed! On the entailment problem for conjunctive queries with safe negation over DL-Lite$_{core}$ knowledge bases

Logic in Computer Science 2026-07-06 v1

Authors: Jerzy Marcinkowski , Piotr Ostropolski-Nalewaja

Abstract

We solve a long standing open problem, showing that the query answering for conjunctive queries with safe negation, over DL-Lite $_{core}$ knowledge bases, is undecidable.

Keywords

description logic DL-Lite_core conjunctive queries safe negation query answering undecidability

Cite

@article{arxiv.2607.05336,
  title  = {Someone slept in my bed! On the entailment problem for conjunctive queries with safe negation over DL-Lite$_{core}$ knowledge bases},
  author = {Jerzy Marcinkowski and Piotr Ostropolski-Nalewaja},
  journal= {arXiv preprint arXiv:2607.05336},
  year   = {2026}
}