[bheadmaster]

> You can think of it as returning an equivalence class if you like. Then it's single-valued.

I can, but I still have to be very mindful of how I use the "=" sign. Sometimes it's an (in)equality, sometimes it's... the equivalence class thing. The ambiguity doesn't seem very elegant.

> Also note the very cool and fun topology connection here. The keyword to search for is Riemann surface.

I'll check that out, thanks.