@MartinSleziak I didn't find any suitable primary tag for this one (I thought of
gm.general-mathematics), and
discrete-geometry is reasonably broad. Actually, it's at the edge of being off-topic. A missing tag would be something related to field/Galois theory (since the field of constructible numbers is lurking behind), but again these are not primary tags. I'd rather recommend not to bump again this question.