Unable to find / detect smallest Gram basis

[tcunis]

The code

grambasis(x^2 + x^4 + x^6)

where x = casos.PS('x'), returns a Gram basis z = [x; x^2; x^3] even though the basis [x; x^3] should be sufficient. In consequence, the function call

grammatrix(casos.PS('q',[x; x^3],'gram'))

fails to detect the Gram matrix.

This is because the function grambasis does not detect that (nor check for) the basis z = [x; x^3] already leads to a monomial x^4 in the product z*z'. I believe that the functions work as desired if the symbolic Gram polynomial is generated with a "full" monomial vector, i.e., [x; x^2; x^3].

Originally posted by @tcunis in #9 (comment)