>is in some sense a single value. In another sense, it is two values.

What I tryed to say is that the sense in which “exactly one element” is used in the definition of function is inclusive of codomain being R^n, so it confused me why you would provide a function that has a codomain of R^2 as something that suggests deviation from the formalism. It just seemed misleading to phrase it that way

I thought consistently would convey the idea I had, nevermind if it doesn’t

My bad about bijectivity, I see it now, you’re right