If I am not mistaken, then:
- the Lorenz attractor $\mathcal{A}$ has Hausdorff dimension $\dim_H(\mathcal{A}) > 2$, and
- the Lorenz attractor $\mathcal{A}$ contains a dense orbit $\mathcal{O}$, i.e. such that $\bar{\mathcal{O}} = \mathcal{A}$.
But:
- the Hausdorff dimension does not satisfy $\dim_H(X) = \dim_H(\bar{X})$ in general,
- for example $\dim_H([0,1] \cap \mathbb{Q}) = 0$ while $\dim_H([0,1]) = 1$.
What is the Hausdorff dimension of a dense orbit in the Lorenz attractor? Is it $\dim_H(\mathcal{A})$, or smaller?