Hyphens, En Dashes, Em Dashes

Q. I’ve read the sections on prefixes and on parentheses with other punctuation, and would be glad if you would weigh in on the following type of structure: (pre)defined or (pre-)defined; (sub)set or (sub-)set. I think it would be reasonable to rule that solid prefixes in parentheses remain solid, and hyphenated prefixes retain their hyphenation. I would generally explain such compact forms before proceeding to use them. Or, if they occur only occasionally, simply expand them. What do you think?

A. Chicago style closes up prefixes whenever possible, and we discourage constructions like (sub)set, which are at worst meaningless and at best ambiguous. “Set or subset” is clearer. Writers who distinguish “defined” from “predefined” should make sure the difference isn’t just of the “sliced/presliced bread” type.