Fractal dimensions in the Gromov–Hausdorff space

We first show that for any four non-negative real numbers, there exists a Cantor ultrametric space whose Hausdorff dimension, packing dimension, upper box dimension, and Assouad dimension are equal to the given four numbers, respectively. Next, using a direct sum of metric spaces, we construct topological embeddings of an arbitrary compact metrizable space into the two subsets of the Gromov–Hausdorff space: the set of all compact metric spaces possessing prescribed topological dimension and the aforementioned four dimensions, and the set of all compact ultrametric spaces.