Given a module M over a commutative unit ring R and a filtration F:...⊆I_2 ⊆I_1 ⊆I_0 = R of ideals of R, the Rees module of M with respect to F is R_+(F, M) = ⊕_(i = 0)^∞ I_i M t^i, which is the set of all formal polynomials in the variable t in which the coefficient of t^i is of the form a m, where a element I_i and m element M. It is a graded module over the Rees ring R_+(F).

associated graded module | Rees ring