6533b823fe1ef96bd127f649

RESEARCH PRODUCT

On the number of factors of Sturmian words

Filippo MignosiFilippo Mignosi

subject

Set (abstract data type)Euler functionCombinatoricssymbols.namesakeRiemann hypothesisGeneral Computer ScienceSturmian wordsymbolsComputer Science(all)Theoretical Computer ScienceMathematics

description

Abstract We prove that for m ⩾1, card( A m ) = 1+∑ m i =1 ( m − i +1) ϕ ( i ) where A m is the set of factors of length m of all the Sturmian words and ϕ is the Euler function. This result was conjectured by Dulucq and Gouyou-Beauchamps (1987) who proved that this result implies that the language (∪ m ⩾0 A m ) c is inherently ambiguous. We also give a combinatorial version of the Riemann hypothesis.

https://doi.org/10.1016/0304-3975(91)90172-x