2018/12/12 by Leader, Imre, Letzter, Shoham, Narayanan, Bhargav +1
#05D05 (Secondary) #20M05 (Primary) #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.1812.04749
In this paper, we study product-free subsets of the free semigroup over a finite alphabet A. We prove that the maximum density of a product-free subset of the free semigroup over A, with respect to the natural measure that assigns a weight of |A|-n to each word of length n, is precisely 1/2.