Published online by Cambridge University Press: 24 June 2010
Let K be a compact subset of ℝd and write s for the Hausdorff dimension of K. For a probability measure μ on K, the lower and upper Lq-dimensions of order q ∈ ℝ are defined byIn this paper we study Lq-dimensions of measures that are generic in the sense of prevalence. In particular, we prove that if K satisfies a mild regularity condition, then a prevalent probability measure μ on K satisfies:for all 0 ≤ q ≤ 1, andfor all 1 ≤ q. This result is in sharp contrast to the behaviour of the Lq-dimensions of measures that are generic in the sense of Baire category. Namely, if K satisfies a mild regularity condition, then a probability measure μ on K that is generic in the sense of Baire category satisfies:for all 1 < q.