Sturmian and Episturmian WordsA "word" here is an infinite sequences of letters, usually from a finite alphabet. "Sturmian" and "episturmian" are defined in terms of complexity of the sequence, where "complexity" is in turn defined in terms of the finite subsequences of the sequence. A good introduction to this can be found at http://congres-math.univ-mlv.fr/sites/congres-math.univ-mlv.fr/files/Arnoux.pdf and http://www-igm.univ-mlv.fr/~berstel/Articles/2007SturmianThessalonique.pdf |