As for the proof of the lemma, it can be derived directly, but a slick way is to show that it is a special case of Hilbert's basis theorem-in fact is essentially the case of ideals generated by monomials.
It can be derived directly. This was as for the proof of the lemma. A slick way is to show that it is a special case of Hilbert's basis theorem-in fact is essentially the case of ideals. These ideals are generated by monomials.