Denis Béchet. NP-Completeness of Grammars Based Upon Products of Free Pregroups. In Claudia Casadio, Bob Coecke, Michael Moortgat, Philip Scott, editors, Categories and Types in Logic, Language, and Physics - Essays Dedicated to Jim Lambek on the Occasion of His 90th Birthday. Volume 8222 of Lecture Notes in Computer Science, pages 51-62, Springer, 2014. [doi]
Abstract is missing.