Published online by Cambridge University Press: 12 October 2015
Let ${\mathcal I}$ be an arbitrary ideal in ${\mathbb C}$[[x, y]]. We use the Newton algorithm to compute by induction the motivic zeta function of the ideal, yielding only few poles, associated to the faces of the successive Newton polygons. We associate a minimal Newton tree to ${\mathcal I}$, related to using good coordinates in the Newton algorithm, and show that it has a conceptual geometric interpretation in terms of the log canonical model of ${\mathcal I}$. We also compute the log canonical threshold from a Newton polygon and strengthen Corti's inequalities.