gfanlib - a Singular interface to Gfanlib and more. ”” is a binary library for Singular that enables basic features of convex geometry through an interface to Gfanlib. It contains cones, polytopes and fans as well as basic functions thereon. Moreover, it contains algorithms for computing Gröbner fans, Gröbner complexes and tropical varieties. For example, given a cone by inequalities and equations, compute its rays and its lineality space, or, given an ideal over the rational numbers, compute its tropical variety with respect to the trivial or the p-adic valuation. This library is part of the official Singular distribution.