On Kakeya Conditions for Achievement Sets

Abstract

AbstractWe prove that for each infinite subset C of $${\mathbb {N}}$$ N there exists a sequence $$(x_n)$$ ( x n ) such that $$\{n: x_n>r_n\}=C$$ { n : x n > r n } = C and the achievement set $$A(x_n)$$ A ( x n ) is a Cantor set. Moreover, we show that it is possible to construct a sequence $$(x_n)$$ ( x n ) such that the set $$\{n: x_n>r_n\}$$ { n : x n > r n } has asymptotic density $$\alpha $$ α for each $$\alpha \in [0,1)$$ α ∈ [ 0 , 1 ) and $$A(x_n)$$ A ( x n ) is a Cantorval.