Definition ccons (t : term) (c : coef) :=
if term_zerop t then c else t :: c.

Lemma cadd_c c1 c2 : {c[cadd c1 c2]} = ({c[c1]} + {c[c2]})%f.
Definition ccmp (c1 c2 : coef) :=
list_compare _ term_cmp c1 c2.