Solution (source code)

= Solution

\b[No.] Take the <hypergraph> with $V=\{a,b\}$ and its single <hyperedge> $\{a,b\}$ of weight $1$. Then $\{a\}\subseteq V$ but $f(\{a\})=1>0=f(V)$, violating the <monotone set function> property. This example already has strictly positive weights.