Re: [math-fun] How do you ask a question in mathematical notation?

When scribbling a math question to myself on a pad of paper, I'll often use notation like ∃? x in X ∋— [condition] [* In case it's illegible in your mail reader: i) the first symbol is a backwards capital E, a "there exists" symbol] ii) the symbol ∋— after the X looks like a pitchfork with the handle to the right. This means "such that". to mean "Does there exist a member of the set X such that [condition] holds?" where the such-that symbol ∋— is something I picked up somewhere from my professors, but haven't seen many other people using it. (To simulate it here I've used the "contains as a member" backwards epsilon special character followed by an em-dash (option-shift-plus on a Mac keyboard).) —Dan