Nash implementation in exchange economies with single-peaked preferences

In exchange economies with single-peaked preferences, we find that: (1) several solutions satisfy Theorem 1 of Doghmi and Ziad [Doghmi, A., Ziad, A., 2008-this issue. Reexamination of Maskin's theorem on Nash implementability. Economics Letters.], (2) strict monotonicity is equivalent to Maskin monotonicity. We examine also the implementation of the weak core in coalitional games.