>
> I have thought about trying, however, to divide up what Maxima does into
> ET -- equivalence transformations --- applying symbolic identities.
> AT -- approximation transformations -- e.g. numerical or symbolic
> approximations
> DT -- derivation approximations -- e.g. take an expression or two and make
> another nonequivalent one. e.g. A+B, diff(A,x), etc.
>
Makes sense. I guess ET includes not only simple default transformations
(general simplifier) but also 'heavy' ones like factorization and polydecomp
(though currently its output form is not understood by Maxima in any
meaningful way).
It sounds like DT is where you put the *formal application* of functions,
and ET is where you put the form-changing part, so
'integrate(x,x) -- DT step combining integrate and x
'integrate(x,x) (ev nouns) => x^2/2 -- ET step changing form
But with your definitions, DT seems like a catch-all, including:
-- construction operators like A+B
-- extraction operators like part(...)
-- analysis operators like solve(...)
-- ? operators like determinant(...)
-- ? operators like rat(...),modulus:2
It looks as though there's room for additional useful classification here.
-s