The numerator is structured like: $$(-b)\pm\sqrt{b^2- 4ac}.$$
Is it confusing or acceptable to distinguish between the following two things?
- An idiom; and
- What is or seems to be a compositionally transparent and faithful representation of meaning. Observe that if we replace expressions (a,b) with either "open_interval_(a,b)" or "ordered_pair_(a,b)", then we have taken a step towards disambiguation. However, that is technically not a matter of direct disambiguation of individual morphograph-like vocabulary items, unless we actually introduce four symbols: open_interval_left_bracket, open_interval_right_bracket, ordered_pair_left_bracket, ordered_pair_right_bracket.
Should "plus or minus" be introduced as an operation, or as an informal notation that is a memory aid, with set theory not being involved?
Suppose that we consider an operation on class variables in set theory: could we get something like an unordered pair of proper classes that isn't merely the empty set, or does this get into an area of taboo, like ancient taboos associated with zero, or more recent taboos associated with infinity or infinitesimals?