- in eja_element.py returns False. Example:
-
- sage: J1 = ComplexHermitianEJA(2)
- sage: J2 = TrivialEJA()
- sage: J = cartesian_product([J1,J2])
- sage: x = J.from_vector(vector(QQ, [-1, -1/2, -1/2, -1/2]))
- sage: x.is_invertible()
- True
- sage: x.det()
- 0
+5. The rational_algebra() stuff doesn't really belong in classes that
+ don't dervice from RationalBasisEJA or its as-yet-nonexistent
+ element class.