Let R = k[x1, . . . , xn] be a polynomial ring over a field k. Let J = {j1, . . . , jt} be a subset of {1, . . . , n}, and let mJ ⊂ R denote the ideal (xj1 , . . . , xjt). Given subsets J1, . . . , Js of {1, . . . , n} and positive integers a1, . . . , as, we study ideals of the form I = m1 J1 ∩ · · · ∩ m as Js . These ideals arise naturally, for example, in the study of fat points, tetrahedral...