Newton-Hensel Interpolation Lifting

Abstract

The main result of this paper is a new version of Newton-Hensel lifting that relates to interpolation questions. It allows one to lift polynomials in $Z[x]$ from information modulo a prime number $p\ne 2$ to a power $p^k$ for any $k$, and its originality is that it is a mixed version that not only lifts the coefficients of the polynomial but also its exponents. We show that this result corresponds exactly to a Newton-Hensel lifting of a system of $2t$ generalized equations in $2t$ unknowns in the ring of $p$-adic integers $\Z_p$. Finally we apply our results to sparse polynomial interpolation in $\Z[x]$