Zdenek Sawa, Petr Jancar. Behavioural Equivalences on Finite-State Systems are PTIME-hard. Computers and Artificial Intelligence, 24(5):513-528, 2005.
@article{SawaJ05, title = {Behavioural Equivalences on Finite-State Systems are PTIME-hard}, author = {Zdenek Sawa and Petr Jancar}, year = {2005}, researchr = {https://researchr.org/publication/SawaJ05}, cites = {0}, citedby = {0}, journal = {Computers and Artificial Intelligence}, volume = {24}, number = {5}, pages = {513-528}, }