An {\omega}-language is a set of infinite words over a finite alphabet X. We consider the class of recursive {\omega}-languages, i.e. the class of {\omega}-languages accepted by Turing machines with a B\"uchi acceptance condition, which is also the class {\Sigma}11 of (effective) analytic subsets of X{\omega} for some finite alphabet X. We investigate here the notion of ambiguity for recursive {\omega}-languages with regard to acceptance by B\"uchi Turing machines. We first present in detail essentials on the literature on {\omega}-languages accepted by Turing Machines. Then we give a complete and broad view on the notion of ambiguity and unambiguity of B\"uchi Turing machines and of the {\omega}-languages they accept. To obtain our new results, we make use of results and methods of effective descriptive set theory.

Source : oai:arXiv.org:1209.5669

DOI : 10.2168/LMCS-10(3:12)2014

Volume: Volume 10, Issue 3

Published on: August 28, 2014

Submitted on: October 2, 2012

Keywords: Computer Science - Logic in Computer Science,Computer Science - Computational Complexity,Mathematics - Logic

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