2 problems

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-…

Let $R$ be a relation, with domain a non-empty set and with any fixed finite arity. For a structure $R$, let $Sib(R)$ denote the number of isomorphism classes of structures equimor…