 (A cofinal set of expressions is a set such that any expression occurs as a constituent in at least one member of the set. Except for very odd languages, the set of all expressions within the language in which some given expression occurs as a constituent is one of many cofinal sets of expressions, so  (F\(_{\textit{all}}\))  follows from (F\(_{\textit{cof}}\)) but not the other way around. That (F\(_{\textit{cof}}\)) follows from  (F\(_{\textit{any}}\))  but not the other way around is trivial.) 