@article{dmtcs:490, title = {New decidable upper bound of the second level in the Straubing-Therien concatenation hierarchy of star-free languages}, author = {Jorge Almeida and Ondrej Klima}, url = {https://dmtcs.episciences.org/490}, doi = {10.46298/dmtcs.490}, journal = {Discrete Mathematics \& Theoretical Computer Science}, issn = {1365-8050}, volume = {Vol. 12 no. 4}, eid = 1, year = {2010}, month = {Jan}, keywords = {formal languages, regular languages, concatenation hierarchies, level two, star-free languages, [INFO.INFO-DM] Computer Science [cs]/Discrete Mathematics [cs.DM]}, language = {English}, }