I try to sort a polynomial using the graded reverse lexicograpic order. According to the Documentation this is achieved via tdeg.
So here is what i tried:

with(Groebner):
sort( x+y+z, order = tdeg(x,y,z));

or

sort(x+y+z, [x,y,z], tdeg);

In both cases maple returns "x+y+z" instead of the expected "z+y+x". What am i doing wrong?

I wrote my own maple library. Some of its procedures require the LinearAlgebra-library.

Is there a way to automatically load LinearAlgebra when loading my library? (I tried to use 'use' but it didnt help )
Currently i load my library with

read "/home/..../something.lib";

Is there any good refernce to learn how to write maple libraries the right way? the maple help isnt actually very helpful.

How can i specify the ground field C= complex numbers and calculate a primary decomposition for an ideal defined over C? For example

with(PolynomialIdeals):
J:= <x^2 +1 >;
PrimaryDecomposition(J);

should return x+I, x-I, but instead returns x^2+1

Here is a standard example of how dcoeffs works:

> with(PDEtools);
> X := a*(diff(y(x), x, x))^2+b*(diff(y(x), x, x))+c*(diff(y(x), x));
                             2                     ...

I  used the DEtools package recently.

When working in a differential algebra with _Envdiffopdomain=[Dt,t] maple still returns something like Dt t^2. I would like him instead to assume, that Dt= dt/t and rewrite it as 2t + t^2 Dt. How can I achieve this behavior?