`   ==Changes, subtle errors == Oleg, I am concerned about the edits that you are making.  My first impression is that it is much harder to understand than it used to be.  It used to be precise as to what it meant; much of that precision has been removed. The result is the sublte introduction of errors...   in part by removing that precision.  For example, the ring over tau_p is not isomorphic to the ring x^n^p which is what you seem to be implying; the degrees of polynomials are totatlly different: if P(tau) is a polynomial, then  n^(deg P(tau)) = deg P(x) one is kind-of-like the exp/ad of the other, sort-of.  And you cut out the paragraphs that made this distinction: tau a is not equal to a tau, but tau a is equal to a^p tau ...  The ring is never commutative when the field is not F_p ...   The field is called F_p not Z/pZ dammit. We already talked about this before. Nobody but you calls it that.  Stating that aP(x) is also additive is important, I don't see why you cut that out.   k{tau} is not k[x] e.g the next theorem to mention is that for any p(x) in k[x] there exists a g(tau) in k{tau} such that f(x) divides g(x).  These g(tau)'s are a left ideal in k{tau}  Using language like ``its quite easy to prove`` and ``it follows quickly`` and ``it can be shown that`` is, at best, filler, and, at worst, misleading as to the actual difficulty of the theorems you are alluding to.  Look, I don't see why you need to be monkeying with this article, why don't you write an article on Ore's invariants of the additive polynomials, or the moore determinant instead, hell, there is no entry for the vandermonde determinant even ...  or start the article on a carlitz module or drinfeld module instead, or fix the article on non-archimedean analysis which really needs a lot of work, cause its missing all that jazz ...    `