To continue on what Joachim and Aaron started discussing: "Add" and co. do not support Basic but they do support Expr. Keeping this in mind should any of the following subclass Expr instead of Basic:
1) AbstractVector (from an imaginary abstract linear algebra module) - I think that it should subclass Expr so we can have sums of AbstractVectors and products of scalars times AbstractVectors - Something should check that we do not create nonsensical stuff like scalar to the power of AbstractVector but this is rather tangential to the discussion 2) MatrixSymbol - same arguments as for 1) 3) Manifold (from my gsoc project) - we want Cartesian products of manifolds. Is this Mul? I think not. Then we subclass from Basic -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
