So I went on trying this but didn't work : 1> g:=n -> sum(a[i]*x^i, i = 1 .. n); 2> a:=Array([0, 5, -4, 6, 7, 2, -2, 0]); # specify the coefficients 3> g(4); # specify the polynom's degree Error, (in g) bad index into Array What is this error ?? In fact, instead of the function in statement 1> I would like to be able to manipulate directly a general polynom with degree n and say multiply it with another generic or given one but then there seems no way out of it ?? Isn't Maple supposed to be a CAS ?? By the way, what are the differences between array() and Array() ? When use one instead of the other ?