$\mathrm{TS}(v,\lambda )$ with cyclic 2-intersecting Gray codes: $v\equiv 0$ or $4(\mathrm{mod}12)$

John Asplund, Melissa Keranen

A $\mathrm{TS}(v,\lambda )$ is a pair $(V,\mathcal{B})$ where $V$ contains $v$ points and $\mathcal{B}$ contains $3$-element subsets of $V$ so that each pair in $V$ appears in exactly $\lambda$ b…