Round trip through Mathematica's FullSimplify
The following command returns 1:
mathematica(-2/(1 + sqrt(3)*I)).FullSimplify().sage()
The issue is that Mathematica simplifies this expression to (-1)/(2/3), which it considers to be defined in terms of the primitive root. Sage on the other hand converts (-1)/(2/3) to 1, with the idea that any root will do. My question: is it a bug that putting this equation into Mathematica and bringing it back to Sage changes it from a complex number to a real number?
By (-1)/(2/3) I think you mean (-1)^(2/3)?