Abstract
We study pregroup grammars with letter promotions $p^{(m)}\Rightarrow q^{(n)}$. We show that the Letter Promotion Problem for pregroups is solvable in polynomial time, if the size of p(n) is counted as |n|+1. In Mater and Fix [11], the problem is shown to be NP-hard, but their proof assumes the binary (or decimal, etc.) representation of n in p(n), which seems less natural for applications. We reduce the problem to a graph-theoretic problem, which is subsequently reduced to the emptiness problem for context-free languages. As a consequence, the following problems are in P: the word problem for pregroups with letter promotions and the membership problem for pregroup grammars with letter promotions.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
