Comment by Gro-Tsen on For which sets do Arthur and Nimue have a winning strategy in this game (“communicate a bit”)?

@user14111 Indeed, if A+N have a winning strategy for $(P',Q')$ and $P\subseteq P'$ and $Q\subseteq Q'$, then A+N have a winning strategy for $(P,Q)$. I should probably have spelled this out explicitly.