-1. Finish DirectSumEJA: add to_matrix(), random_instance(),
- one()... methods. Make it subclass RationalBasisEuclideanJordanAlgebra.
- This is not a general direct sum / cartesian product implementation,
- it's used only with the other rationalbasis algebras (to make non-
- simple EJAs out of the simple ones).
+1. Finish CartesianProductEJA: add to_matrix(), random_instance(),...
+ methods. I guess we should create a separate class hierarchy for
+ Cartesian products of RationalBasisEJA? That way we get fast
+ charpoly and random_instance() defined...
2. Add references and start citing them.
sage: F = J.base_ring()
sage: a0 = (1/4)*X[4]**2*X[6]**2 - (1/2)*X[2]*X[5]*X[6]**2 - (1/2)*X[3]*X[4]*X[6]*X[7] + (F(2).sqrt()/2)*X[1]*X[5]*X[6]*X[7] + (1/4)*X[3]**2*X[7]**2 - (1/2)*X[0]*X[5]*X[7]**2 + (F(2).sqrt()/2)*X[2]*X[3]*X[6]*X[8] - (1/2)*X[1]*X[4]*X[6*X[8] - (1/2)*X[1]*X[3]*X[7]*X[8] + (F(2).sqrt()/2)*X[0]*X[4]*X[7]*X[8] + (1/4)*X[1]**2*X[8]**2 - (1/2)*X[0]*X[2]*X[8]**2 - (1/2)*X[2]*X[3]**2*X[9] + (F(2).sqrt()/2)*X[1]*X[3]*X[4]*X[9] - (1/2)*X[0]*X[4]**2*X[9] - (1/2)*X[1]**2*X[5]*X[9] + X[0]*X[2]*X[5]*X[9]
-5. The main EJA element constructor is happy to convert between
- e.g. HadamardEJA(3) and JordanSpinEJA(3).
-
-6. Profile the construction of "large" matrix algebras (like the
+5. Profile the construction of "large" matrix algebras (like the
15-dimensional QuaternionHermitianAlgebra(3)) to find out why
they're so slow.
-
-7. Drop the element-subalgebra in favor of a regular subalgebra. The
- cached "one" can be set in the method.