A Journey to the Frontiers of Query Rewritability

  title={A Journey to the Frontiers of Query Rewritability},
  author={Piotr Ostropolski-Nalewaja and Jerzy Marcinkowski and David Carral and Sebastian Rudolph},
  journal={Proceedings of the 41st ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems},
We consider (first-order) query rewritability in the context of theory-mediated query answering. The starting point of our journey is the FUS/FES conjecture, which states that any theory that is a finite expansion set (FES) and admits query rewriting (BDD, FUS) must be uniformly bounded. We show that this conjecture holds for a large class of BDD theories, which we call "local". Upon investigating how "non-local" BDD theories can actually get, we discover unexpected phenomena that, we think… 

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