Restricted ambiguity of erasing morphisms
conference contributionposted on 2010-09-08, 15:20 authored by Daniel Reidenbach, Johannes C. Schneider
A morphism h is called ambiguous for a string s if there is another morphism that maps s to the same image as h; otherwise, it is called unambiguous. In this paper, we examine some fundamental problems on the ambiguity of erasing morphisms. We provide a detailed analysis of so-called ambiguity partitions, and our main result uses this concept to characterise those strings that have a morphism of strongly restricted ambiguity. Furthermore, we demonstrate that there are strings for which the set of unambiguous morphisms, depending on the size of the target alphabet of these morphisms, is empty, finite or infinite. Finally, we show that the problem of the existence of unambiguous erasing morphisms is equivalent to some basic decision problems for nonerasing multi-pattern languages.
- Computer Science
CitationREIDENBACH, D. and SCHNEIDER, J.C., 2010. Restricted ambiguity of erasing morphisms. 14th International Conference on Developments in Language Theory, DLT 2010, August 17-20, 2010, London, Ontario, Canada.
Publisher© Springer Verlag
- AM (Accepted Manuscript)
NotesThis conference paper was subsequently published as: REIDENBACH, D. and SCHNEIDER, J.C., 2010. Restricted ambiguity of erasing morphisms. IN: Gao, Y. ... et al (eds). Proceedings of the 14th International Conference on Developments in Language Theory, DLT 2010. Lecture Notes in Computer Science, Vol. 6224, pp.387-398.
Book seriesLecture Notes in Computer Science;6224