Complexity of Suffix-Free Regular Languages

Abstract

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.jcss.2017.05.011 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/We study various complexity properties of suffix-free regular languages. A sequence (Lk,Lk+1,…) of regular languages in some class, where n is the quotient complexity of Ln, is most complex if its languages Ln meet the complexity upper bounds for all basic measures. It is known that there exist such most complex sequences in several classes of regular languages. In contrast to this, we prove that there does not exist a most complex sequence in the class of suffix-free regular languages. However, we do exhibit two such sequences that together meet upper bounds for all basic measures.Natural Sciences and Engineering Research Council of Canada (NSERC) grant No. OGP000087National Science Centre, Poland project number 2014/15/B/ST6/0061