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eja: add a TODO for a bug just observed.
[sage.d.git] / mjo / eja / TODO
1 1. Add cartesian products to random_eja().
2
3 2. Add references and start citing them.
4
5 3. Implement the octonion simple EJA.
6
7 4. Pre-cache charpoly for some small algebras?
8
9 RealSymmetricEJA(4):
10
11 sage: F = J.base_ring()
12 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]
13
14 5. Profile the construction of "large" matrix algebras (like the
15 15-dimensional QuaternionHermitianAlgebra(3)) to find out why
16 they're so slow.
17
18 6. We should compute whether or not the algebra is associative if it
19 is unknown. I guess the "associative" argument should be ternary
20 (True, False, None)? We should also figure out the correct
21 True/False values for the example classes, and of course add an
22 _is_associative() method.
23
24 7. When field=RDF, subalgebra construction is failing because the
25 inner product isn't associative? Actually, it's the combination
26 of field=RDF and orthonormalize=True.