Threshold automata, and the counter systems they define, were introduced as a framework for parameterized model checking of fault-tolerant distributed algorithms. This application domain suggested natural constraints on the automata structure, and a specific form of acceleration, called single-rule acceleration: consecutive occurrences of the same automaton rule are executed as a single transition in the counter system. These accelerated systems have bounded diameter, and can be verified in a complete manner with bounded model checking. We go beyond the original domain, and investigate extensions of threshold automata: non-linear guards, increments and decrements of shared variables, increments of shared variables within loops, etc., and show that the bounded diameter property holds for several extensions. Finally, we put single-rule acceleration in the scope of flat counter automata: although increments in loops may break the bounded diameter property, the corresponding counter automaton is flattable, and reachability can be verified using more permissive forms of acceleration.
@InProceedings{kukovec_et_al:LIPIcs.CONCUR.2018.19, author = {Kukovec, Jure and Konnov, Igor and Widder, Josef}, title = {{Reachability in Parameterized Systems: All Flavors of Threshold Automata}}, booktitle = {29th International Conference on Concurrency Theory (CONCUR 2018)}, pages = {19:1--19:17}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-087-3}, ISSN = {1868-8969}, year = {2018}, volume = {118}, editor = {Schewe, Sven and Zhang, Lijun}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2018.19}, URN = {urn:nbn:de:0030-drops-95578}, doi = {10.4230/LIPIcs.CONCUR.2018.19}, annote = {Keywords: threshold \& counter automata, parameterized verification, reachability} }
Feedback for Dagstuhl Publishing