Fonda, AlessandroKlun, Giuliano2019-03-072019-03-072019-03-07https://openscience.sissa.it/handle/1963/35330The classical Poincaré–Bohl theorem provides the exis-tence of a zero for a function avoiding external rays. When the do-main is convex, the same holds true when avoiding normal cones. We consider here the possibility of dealing with nonconvex sets having in-ward corners or cusps, in which cases the normal cone vanishes. This allows us to deal with situations where the topological degree may be di˙erent from ±1.enPoincaré–Bohltopological degreeavoiding cones conditionPreprint04/2019/MATE