On the 430-cap of $\mathrm{PG}(6,4)$ having two intersection sizes with respect to hyperplanes

Abstract

Let $\mathcal{C}$ be a 430-cap of $\mathrm{PG}(6,4)$ having two intersection sizes with respect to hyperplanes. We show that no hyperplane of $\mathrm{PG}(6,4)$ intersects $\mathcal{C}$ in a Hill 78-cap. So if it can be shown that the Hill 78-cap of $\mathrm{PG}(5,4)$ is projectively unique, then such a 430-cap does not exist, or equivalently, a two-weight $[430,7]_{\mathbb{F}_4}$ linear code with dual weight at least 4, does not exist.