### A dyadic view of rational convex sets

Let $F$ be a subfield of the field $\mathbb{R}$ of real numbers. Equipped with the binary arithmetic mean operation, each convex subset $C$ of ${F}^{n}$ becomes a commutative binary mode, also called idempotent commutative medial (or entropic) groupoid. Let $C$ and ${C}^{\text{'}}$ be convex subsets of ${F}^{n}$. Assume that they are of the same dimension and at least one of them is bounded, or $F$ is the field of all rational numbers. We prove that the corresponding idempotent commutative medial groupoids are isomorphic iff the affine space ${F}^{n}$...