@article{Bodirsky_Knäuer_2021, title={Network Satisfaction for Symmetric Relation Algebras with a Flexible Atom}, volume={35}, url={https://ojs.aaai.org/index.php/AAAI/article/view/16773}, DOI={10.1609/aaai.v35i7.16773}, abstractNote={Robin Hirsch posed in 1996 the Really Big Complexity Problem: classify the computational complexity of the network satisfaction problem for all finite relation algebras A. We provide a complete classification for the case that A is symmetric and has a flexible atom; the problem is in this case NP-complete or in P. If a finite integral relation algebra has a flexible atom, then it has a normal representation B. We can then study the computational complexity of the network satisfaction problem of A using the universal-algebraic approach, via an analysis of the polymorphisms of B. We also use a Ramsey-type result of Nešetřil and Rödl and a complexity dichotomy result of Bulatov for conservative finite-domain constraint satisfaction problems.}, number={7}, journal={Proceedings of the AAAI Conference on Artificial Intelligence}, author={Bodirsky, Manuel and Knäuer, Simon}, year={2021}, month={May}, pages={6218-6226} }