Sums of finitely many distinct rationals

Donald Silberger, Sylvia Silberger, David Hobby

$\mathcal{E}$ denotes the family of all finite nonempty $S\subseteq \mathbb{N}:=\{1,2,\dots \}$, and $\mathcal{E}(X):=\mathcal{E}\cap \{S:S\subseteq X\}$ when $X\subseteq \mathbb{N}$. Simila…