I came across this question, which was tagged "linear algebra". I wasn't sure what to retag it as. I thought about (logic), but that's for advanced mathematical logic, model theory and whatnot. We need a tag which is to (logic) what (elementary-set-theory) is to (set-theory), or what (probability) is to (probability-theory). The tag description for (logic) suggests (puzzles), which is not a good fit here.
What tag should be used for questions like this?
Can we mention that tag in the tag description for (logic)?