The cyclicity problem for the images of Q-rational series
Department of Mathematics, University of Turku, 20014 Turku, Finland
Received: 31 May 2010
Accepted: 27 June 2011
We show that it is decidable whether or not a given Q-rational series in several noncommutative variables has a cyclic image. By definition, a series r has a cyclic image if there is a rational number q such that all nonzero coefficients of r are integer powers of q.
Mathematics Subject Classification: 11B85 / 11U05 / 68Q45
Key words: Rational series / images of rational series / decidability
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