Module NatSet := FSetList.Make(OrderedTypeEx.Nat_as_OT).Infix "++" := add (at level 60, right associativity).Notation "s [=] t" := (Equal s t) (at level 70, no associativity).Module GeneralProperties := FSetProperties.Properties NatSet.

Theorem AMM11262: {e:elt | In e town /\ forall u, In u town /\ ~(E.eq u e)-> knows e u}.