Let M be an R = k[x1,...,xn]/J-module (for example an ideal), and let mm=ideal vars R = (x1,...,xn), and suppose that M is a homomorphic image of the free module F. Let T be the Rees algebra of M. The call specialFiberIdeal(M) returns the ideal J⊂Sym(F) such that Sym(F)/J ≅T/mm*T; that is, specialFiberIdeal(M) = reesIdeal(M)+mm*Sym(F).
i1 : R=QQ[a,b,c,d,e,f] o1 = R o1 : PolynomialRing |
i2 : M=matrix{{a,c,e},{b,d,f}} o2 = | a c e | | b d f | 2 3 o2 : Matrix R <--- R |
i3 : analyticSpread image M o3 = 3 |
i4 : specialFiberIdeal image M o4 = ideal (f, e, d, c, b, a) o4 : Ideal of R[w , w , w ] 0 1 2 |