5. Factor out the unit-norm basis (and operator symmetry) tests once
all of the algebras pass.
-6. Implement random_instance() for the main EJA class.
-
-7. Implement random_instance() for the subalgebra class.
+6. Can we make the minimal and characteristic polynomial tests work
+ for trivial algebras, too? Then we wouldn't need the "nontrivial"
+ argument to random_eja().