Abstract
This paper is a continuation of the study of topological properties of omega context free languages (ω-CFL). We proved in (Topological properties of omega context free languages, Theoretical Computer Science, 262 (1–2) (2001) 669–697) that the class of ω-CFL exhausts the finite ranks of the Borel hierarchy, and in (Borel hierarchy and omega context free languages, Theoretical Computer Science, to appear) that there exist some ω-CFL which are analytic but non Borel sets. We prove here that there exist some omega context free languages which are Borel sets of infinite (but not finite) rank, giving additional answer to questions of Lescow and Thomas [Logical specifications of infinite computations in: “A Decade of Concurrency” (J.W. de Bakker et al. (Eds.), Springer LNCS 803 (1994) 583–621).
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.
