Week 2

In the second week, I implemented the lift_newton function that is used to lift coprime index 1 factorizations. plug_delta, coeffx, coefs_operator and coefs_poly were the helper functions used in the process. coefs_operator takes a polynomial and returns an operator with the given valuation, while coefs_poly takes an operator and returns a polynomial after extracting its relevant part. plug_delta simply converts a polynomial to a differential operator by substituting δ = xD in place of x. coeffx(f, e) returns the coefficient of x^e in f while simultaneously substituting x in the place of δ. The initial version of lift_newton that I implemented was buggy, but thanks to the review on the mailing list, I was able to correct it. The plan now is to tie up any loose ends in the functions finished so far which all deal with factorization using the Newton method. If there are no more problems with them, then I'll go on to implement the functions related to factorization using a Riccati solution : factor_riccati and ramification_of. That's all from me. Good-bye, until next time.