Resumen.Si hay un cardinal desdoblable entonces hay una extensión forcing con una (ω₂,1)-morass simplificada y ninguna (ω₁,1)-morass simplificada con límites lineales.

Abstract. If there is a strongly unfoldable cardinal then there is a forcing extension with a simplified (ω₂,1)-morass and no simplified (ω₁,1)-morass with linear limits.