As a followup, if anyone is interested, there is a fairly tractable paper on computing cube roots in a modular field at http://eprint.iacr.org/2009/457.pdf . It does not appear that this is implemented yet:
```python >>> m7(4)**Rational(1,3) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "sympy\polys\domains\modularinteger.py", line 129, in __pow__ return self.__class__(val**exp) File "sympy\polys\domains\modularinteger.py", line 18, in __init__ self.val = self.dom.convert(val) % self.mod File "sympy\polys\domains\domain.py", line 103, in convert return K1.from_sympy(a) File "sympy\polys\domains\pythonintegerring.py", line 34, in from_sympy raise CoercionFailed("expected an integer, got %s" % a) sympy.polys.polyerrors.CoercionFailed: expected an integer, got 2**(2/3) ``` -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.