Usage: <normal_conecone J T L Compute the graded ring T/L = R/J + J/J^2 + J^2/J^3 + ..., where R is the base ring of J, and T is a polynomial ring over R supplied by the user. T/L corresponds to the normal cone of the scheme defined by J. Parameters: J = an ideal. T = a polynomial ring over R in variables whose weights are proportional to the degrees of the generators of J. Output values: L = the result ideal in the ring T. The ring R may be a quotient ring. The normal cone is computed by writing R[tJ] = T/L1. Then the ideal L = L1 + JT.