“…Therefore, under the condition (2) of 1.2, we get a graded S-free resolution of R(I), and taking its homogeneous part of degree r ∈ Z, we get an R-free resolution of I r , from which we can deduce some homological properties of powers of I. In the subsequent paper [3], using the R-free resolution of I r constructed in this way, we study the associated prime ideals of R/I r and compute the saturation of I m . So, the author thinks that 1.2 is very convenient and it may have more application.…”