Traceback (most recent call last):
  File "run/609b446b073f546cc37a9cd52b5d29ca492b66a5.py", line 117, in <module>
    print isidentity((ud1*(ux5+uy5)+ud2*(ux5**_sage_const_2 +uy5**_sage_const_2 ))-((ux5+ux5**_sage_const_2 )*(uy5+uy5**_sage_const_2 ))) or isidentity(uy1*uy1*uy2*uy3*ux1*ux1*ux2*ux3*((ud1*(ux5+uy5)+ud2*(ux5**_sage_const_2 +uy5**_sage_const_2 ))-((ux5+ux5**_sage_const_2 )*(uy5+uy5**_sage_const_2 ))))
  File "run/609b446b073f546cc37a9cd52b5d29ca492b66a5.py", line 62, in isidentity
    return x.iszero()
  File "run/609b446b073f546cc37a9cd52b5d29ca492b66a5.py", line 25, in iszero
    return self.top in I and not (self.bot in I)
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/rings/ideal.py", line 228, in __contains__
    return self._contains_(self.__ring(x))
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 2072, in _contains_
    g = f.reduce(self.groebner_basis())
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/misc/cachefunc.py", line 242, in __call__
    cache[key] = self.f(self._instance, *args, **kwds)
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 1962, in groebner_basis
    gb = self._groebner_basis_singular("groebner", *args, **kwds)
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 319, in wrapper
    with RedSBContext():
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/rings/polynomial/multi_polynomial_ideal.py", line 288, in __enter__
    self.o = self.singular.option("get")
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/interfaces/singular.py", line 976, in option
    return self(self.eval("option(get)"),"intvec")
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/interfaces/singular.py", line 482, in eval
    s = Expect.eval(self, x)
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/interfaces/expect.py", line 937, in eval
    return 'n'.join([self._eval_line(L, **kwds) for L in code.split('n') if L != ''])
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/interfaces/expect.py", line 633, in _eval_line
    self._start()
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/interfaces/singular.py", line 336, in _start
    Expect._start(self, alt_message)
  File "/home/sage/sage-3.2.3/local/lib/python2.5/site-packages/sage/interfaces/expect.py", line 470, in _start
    raise RuntimeError, "Unable to start %s"%self.__name
RuntimeError: Unable to start singular