params, a matrix, S is the iterated tower ring A[x(0,0)..x(0,d1)]..[..x(n,dn)] reprsenting the product PAd1 x ..x PAdn, where the products are relative to A, and params is a system of multilinear forms in S. They are sparse if M is not present, or determined by M if it is.
See also
pureResolution -- creates a pure resolution as an iterated direct image