1. Add CartesianProductEJA.
-2. Check the axioms in the constructor when check != False?
+2. Add references and start citing them.
-3. Add references and start citing them.
+3. Implement the octonion simple EJA.
-4. Implement the octonion simple EJA.
+4. Override random_instance(), one(), et cetera in DirectSumEJA.
-5. Factor out the unit-norm basis (and operator symmetry) tests once
- all of the algebras pass.
+5. Switch to QQ in *all* algebras for _charpoly_coefficients().
+ This only works when we know that the basis can be rationalized...
+ which is the case at least for the concrete EJAs we provide,
+ but not in general.
-6. Implement spectral projector decomposition for EJA operators
- using jordan_form() or eigenmatrix_right(). I suppose we can
- ignore the problem of base rings for now and just let it crash
- if we're not using AA as our base field.
+6. Pass already_echelonized (default: False) and echelon_basis
+ (default: None) into the subalgebra constructor. The value of
+ already_echelonized can be passed to V.span_of_basis() to save
+ some time, and usinf e.g. FreeModule_submodule_with_basis_field
+ we may somehow be able to pass the echelon basis straight in to
+ save time.
-7. Do we really need to orthonormalize the basis in a subalgebra?
- So long as we can decompose the operator (which is invariant
- under changes of basis), who cares?
+ This may require supporting "basis" as a list of basis vectors
+ (as opposed to superalgebra elements) in the subalgebra constructor.
-8. Ensure that we can construct all algebras over both AA and RR.
-
-9. Check that our field is a subring of RLF.
+7. Use charpoly for inverse stuff if it's cached.