2 problems

Direct-sum conjecture for transversal q-matroids. The direct sum $M_1\oplus M_2$ is a transversal $q$-matroid with presentation $\mathcal{X}_1\oplus\mathcal{X}_2$.

Let a DSC be a direct sum of chains, and let $Sib(\mathcal{D})$ denote its sibling number. Suppose … is a countable DSC, where $\mathcal{D}_1$ is bounded, $\mathcal{D}_2$ is a non-…