X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo%2Feja%2FTODO;h=ed15aa3dd5443c18195d9548c44e4a208a601dd7;hb=b44ddab3076cc3b01c95bf6eb3b5f7b20dfd7913;hp=220a70193014f215b25758fe39f42c82e1fbfbc4;hpb=0cd1482ab4d38ca850e2f6ee1203038c8cbd9bb1;p=sage.d.git

diff --git a/mjo/eja/TODO b/mjo/eja/TODO
index 220a701..ed15aa3 100644
--- a/mjo/eja/TODO
+++ b/mjo/eja/TODO
@@ -14,16 +14,14 @@
 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
+   some time, and using e.g. FreeModule_submodule_with_basis_field
    we may somehow be able to pass the echelon basis straight in to
    save time.
 
    This may require supporting "basis" as a list of basis vectors
    (as opposed to superalgebra elements) in the subalgebra constructor.
 
-7. Use charpoly for inverse stuff if it's cached.
-
-8. The inner product should be an *argument* to the main EJA
+7. The inner product should be an *argument* to the main EJA
    constructor.  Afterwards, the basis normalization step should be
    optional (and enabled by default) for ALL algebras, since any
    algebra can have a nonstandard inner-product and its basis can be
@@ -31,3 +29,21 @@
    HadamardEJA could be equipped with an inner- product that is twice
    the usual one. Then for the basis to be orthonormal, we would need
    to divide e.g. (1,0,0) by <(1,0,0),(1,0,0)> = 2 to normalize it.
+
+8. Pre-cache charpoly for some small algebras?
+
+RealSymmetricEJA(4):
+
+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]
+
+9. Compute the scalar in the general natural_inner_product() for
+   matrices, so no overrides are necessary.
+
+10. The main EJA element constructor is happy to convert between
+    e.g. HadamardEJA(3) and JordanSpinEJA(3).
+
+11. Figure out if CombinatorialFreeModule's use of IndexedGenerators
+    can be used to replace the matrix_basis().
+
+12. Move the "field" argument to a keyword after basis, jp, and ip.